ANALYZED

. . ' r . .

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NATIONAL RESEARCH COUNCIL OF CANADA

DIVISION OF BUILDING RESEARCH

AVALANCHE ACCIDENTS IN CANADA

11. A SELECTION OF CASE HISTORIES

OF ACCIDENTS 1943 TO 1978

b Y

C.J. Stethem and P.A. Schaerer

DBR Paper No. 926

of the

Division of Building Research

OTTAWA, July 1980

AVALANCHE ACCIDENTS IN CANADA

11. A SELECTION OF CASE HISTORIES OF ACCIDENTS 1943 TO 1978

by C.J. Stethem and P.A. Schaerer

ABSTRACT

Case histories are presented of avalanche accidents in Canada that resulted in death or injury. A first volume describing accidents between 1955 and 1976 was published earlier (NRCC 17292). The present publication contains cases from the winters 1976 to 1978 and a few selected ones from earlier years. They contain a description of the weather, snow conditions, circumstances leading to the accident, the event, and the rescue operation.

ACCIDENTS CAUS~S PAR LES AVALANCHES AU CANADA

11. CHOIX DE CAS DOCUMENT~S D'ACCIDENTS DE 1943 1978

par C.J. Stethem and P.A. Schaerer

Des cas dlaccidents caus6s par des avalanches au Canada ayant provoqug la mort ou des blessures sont pr6sentGs. Un premier volume dgcrit les accidents qui se sont produits entre 1955 et 1976 a 6t6 publigs plus t6t (NRCC 17292). Cette publication contient les cas des hivers de 1976 5 1978 et certains autres cas choisis dans le rgpgrtoire des ann6es pr6cGdentes. Les cas documenti% contiennent une description de la tempgrature, des conditions de la neige, des circonstances qui ont conduit 2 l'accident, l'accident comme tel, et 110p6ration de sauvetage.

FOREWORD

The objective of the avalanche research program of the Division of Building Resea~ch of the National Research Council is to develop and make available information about snow avalanches and protection from them. In partial fulfillment of this objective, case histories of accidents were collected that either resulted in death, injury, or property damage or have educational value. A first volume describing 40 accidents between 1955 and 1976 was published earlier (NRCC 17292). The present publication contains the accident cases of the two winters between 1976 and 1978 and some additional ones from earlier years.

The case histories presented in this report were collected by Mr. Chris Stethem, working on Contract OSS77-08171 with the National Research Council of Canada. Mr. Stethem obtained the information from published reports, from files of agencies and through interviews with persons who were either eyewitnesses to the accident or involved in the rescue operation.

The reader will notice an increase in the amount of information concerning individual accidents towards the end of this report. The most recent cases are well documented with weather, snowpack and avalanche observations. This is a reflection of a growth in interest and knowledge of personnel working in avalanche areas, which in some part, is the result of education in which the National Research Council played an important role by developing avalanche course programs, assisting in instruction and through publications such as this one.

The compilation of accident case histories will continue, and publication of a further volume containing the numerous accidents and destructive avalanches of February 1979 is anticipated. Furthermore it is planned to collect statistics about the numerous encounters that have not resulted in death, injury, or serious property damage. The assistance of individuals and agencies who make available information is gratefully acknowledged, and it is expected that the same co-operation will continue.

Ottawa July 1980

C.B. Crawford Director, DBR/NRC

ACKNOWLEDGEMENT

The National Research Council wishes to express its thanks to the following agencies, organizations, and individuals who have contributed information.

Apex Alpine Recreations Ltd.

Atmospheric Environment Service Canada

British Columbia Ministry of Transportation and Highways

British Columbia Ministry of Lands, Parks and Housing

British Columbia Ministry of the Attorney-General

Canadian Mountain Holidays

Canadian National Railways

Garibaldi Lifts Limited

Ocean Falls Corporation

Parks Canada

Suret6 de Quebec

Workers Compensation Board of British Columbia

B. Geisler

W. Jenkins

W. Kleinschrot

R. Neville

C. Sadleir

LIST OF THE ACCIDENTS

11 February

23 February

14 January

27 March

23 February

24 March

7 April

19 July

21 January

13 January

11 August

14 March

13 February

11 June

11 December

12 December

28 December

15 February

16 March

17 March

19 March

21 March

27 March

30 March

7 September

9 October

8 March

Kwinitsa Workmen killed, Construction camp destroyed

Fraser Canyon Person on road killed

Fraser Canyon Workman killed

Seymour Inlet Workman killed

Woodbury Creek Person on road killed

McGillivray Pass Skiers killed

Torbit Mine Workman killed

Mt. Garibaldi Mountain climber killed

Silver Star Skier killed

Ocean Falls Persons in buildings killed, buildings destroyed

Mt. St. Elias Mountain climbers killed

Nine Mile Mountain Snowmobile operator killed

Westcastle Workman injured

Mt. Fisher Mountain climbers injured

Sunshine Village Skier buried

Chancellor Peak

Tadoussac

Parker Ridge

Diana Lake

Bugaboo

Bow Peak

Apex Mountain

Quartz Ridge

Lake Louise

Mt. Athabasca

President's Col

Whistler Mountain

Mountain climbers killed

Snowmobile operator killed

Skier killed

Skier killed

Skiers killed

Mountain climber killed

Skier killed

Skier killed

Skier killed

Mountain climbers injured

Mountain climber killed

Skiers buried

PREFACE

The list of accidents described in this publication is a reflection of the change in activities in the mountains of Western Canada and the shift in the type of involvements with avalanches. In the years before 1960 avalanche accidents occurred mainly on roads and in work areas such as construction, mining and logging, but when recreation in the mountains became more popular the number of acctdents involving skiers and mountain climbers increased. On the average seven people per year have died in avalanches in Canada between 1970 and 1978, the period when accurate records were maintained. With 13 deaths the winter of 1976-1977 was above average, and all 13 persons were involved in recreational activities.

Three important conclusions can be drawn from features common to several cases.

1. The time for survival of persons completely encased in the snow is very short. This means that live rescue depends on the quick action of the accident witnesses who must immediately search likely areas of burial. Obviously rescue transceivers and probes assist greatly in locating buried victims, and shovels carried by the rescuers are essential for a quick recovery.

2. Several persons on roads and on skis have died when a second avalanche ran after the first one. For this reason danger from later avalanches and proper safety measures must be considered in rescue and snow removal operations.

3 . Some skiers were caught in avalanches on slopes that had been treated with artillery fire a short time before. When a deep slab instability exists such slopes may be considered safe only when avalanches were actually observed and the unstable snow removed.

KWINITSA, SKEENA RIVER VALLEY, B.C. 11 FEBRUARY 1943

Three men k i l l e d , eleven i n j u r e d , seve ra l bui ld ings destroyed

WEATHER

Observations a t Terrace Ai rpor t , 60 m ASL

Temperature P r e c i p i t a t i o n O c

Date Max Min mm

7 February 4.5 3.0 45

8 February 3.5 0.5 3 0

9 February 4.0 -0.5 5.5

10 February 0.5 -6.5

11 February 0 -3.5 2.5

Experience has shown t h a t warm moisture laden f r o n t s usua l ly a r r i v e e a r l i e r and deposi t more snow a t t h e acc ident s i t e than a t Terrace. On 12 and 13 February a t o t a l of 51 mm of p r e c i p i t a t i o n was recorded a t Terrace Airpor t .

SITUATION

The accident s i t e was a t McLean Point on t h e shore of the Skeena River 85 km west of Terrace. A cons t ruct ion camp t o house workmen bui ld ing t h e highway from Terrace t o Prince Rupert was located bes ide t h e rai lway t r a c k s i n t h e runout zone of a l a rge avalanche gul ly .

In t h e e a r l y winter of 1942-43 o f f i c i a l s of t h e Canadian National Railway v i s i t e d t h e camp and warned t h e superintendent of t h e avalanche danger. In January 1943 an avalanche descended t h e gu l ly and blocked about 30 m of t h e rai lway t r ack but d id not reach t h e camp. A r a i l r o a d engineer again v i s i t e d t h e camp and t o l d of a snowshed t h a t had been destroyed a t t h e same s i t e about 10 years e a r l i e r .

By e a r l y February t h e avalanche hazard had become t h e c e n t r a l t o p i c of d iscuss ion among t h e 200 men working i n t h e camp. During t h e second week of February a storm raged i n t h e a rea . Most of t h e p r e c i p i t a t i o n f e l l a s

r a i n a t t h e lower e l eva t ions , but on t h e n igh t of 10 February snow was deposi ted a t the camp.

ACCIDENT SUMMARY

A t about 0730 h on 11 February most of t h e men had f in i shed break- f a s t and were preparing t o leave f o r work, when suddenly a rumbling was heard. An avalanche swept down t h e g u l l y and s t ruck t h e camp carry ing away two small bunkhouses and t h e f i r s t a i d shack. Several men were caught. One of them who had been s tanding by a 14-ton locomotive was crushed by t h e moving snow and d e b r i s , and another one close-by was swept away and buried. Those who escaped t h e avalanche aided t h e in ju red , moving them t o t h e remaining bunkhouses and then, because o the r avalanches seemed imminent, t o t h e patrolmen's shack a t Telegraph Point , 2 km west. Other survivors remained behind and searched f o r those s t i l l missing.

A s t h e in ju red men were being moved a second s l i d e s t ruck , and destroyed t h e two remaining bunkhouses. Several men were p a r t i a l l y buried and some were c a r r i e d i n t o t h e r i v e r . Only t h e o f f i c e a t t h e e a s t end of t h e camp and t h e commissary a t t h e west end remained standing. About twenty minutes l a t e r , when t h e remaining men were moving t o sa fe ty , a t h i r d avalanche s t ruck des t roying t h e o f f i c e .

RESCUE

A westbound passenger t r a i n a r r ived a t t h e s i t e about one and one h a l f hours a f t e r t h e f i r s t avalanche. Two doctors on board crossed t h e avalanche deposi t t o a i d t h e in ju red .

Two men remained missing and severa l were incapac i t a t ed with i n j u r i e s . Word reached Prince Rupert by te legraph and a h o s p i t a l t r a i n was dispatched t o t h e s i t e t h e following morning. During t h e r e t u r n t r i p one man died of i n j u r i e s ; eleven were hosp i t a l i zed .

On 15 February t h e body of one of t h e missing men was located , but the o the r one was never found. Presumably it was c a r r i e d away by t h e r i v e r . A few days l a t e r t h e camp was r e b u i l t i n a s a f e pos i t ion a t Telegraph Point .

AVALANCHE

The McLean Point avalanche f e l l some 1000 m v e r t i c a l l y onto t h e rai lway and highway. The s t a r t i n g zone of sou the r ly aspect was i n a s t eep , wide g r a n i t e g u l l y covered with mixed sparse vegeta t ion . The avalanche t r a c k was a s t e e p sided g u l l y with an average gradient of 34O. Approximately 100 m above t h e rai lway and t h e highway t h e g u l l y opened i n t o an a l l u v i a l fan covered with shrubs.

COMMENT

The Skeena River Val ley between Terrace and Pr ince Rupert i s one of t h e most a c t i v e avalanche a r e a s i n B r i t i s h Columbia where avalanches f r e q u e n t l y block t h e r a i lway and t h e highway. Considering t h e f requent avalanches and t h e heavy annual snowfal l i n t h e a r e a it should be obvious even t o a layman t h a t t h e s t e e p g u l l y a t McLean Poin t would be an avalanche t r a c k . I t i s hard t o b e l i e v e t h a t a cons t ruc t ion camp was b u i l t t h e r e and maintained dur ing t h e win te r . The reason was probably t h a t over a d i s t a n c e of s e v e r a l k i lome te r s t h e r e i s l i t t l e space between t h e s t e e p mountain and t h e r i v e r , t h e r e f o r e t h e a l l u v i a l f an a t t h e t o e of McLean Mountain was p a r t i c u l a r l y a t t r a c t i v e .

The ra i lway s t a f f was aware of t h e avalanche hazard , because a snow shed had once covered t h e t r a c k s a t t h i s s i t e and was des t royed 18 Apr i l 1933. Unfor tuna te ly t h e managers o f t h e highway cons t ruc t ion company d i d n o t heed t h e warnings. The i r excuse was t h a t t hey had planned t o complete t h e job be fo re t h e win te r , bu t obviously they gambled h e a v i l y and l o s t when it was no t .

This ca se proves t h a t s e v e r a l d e s t r u c t i v e avalanches may run i n t h e same pa th du r ing t h e same storm and o f t e n wi th in a s h o r t t ime o f each o t h e r . For t h i s reason t h e danger from f u r t h e r avalanches must be a pr imary concern f o r t h e l e a d e r o f any avalanche r e scue mission.

Figure 1 View of t h e avalanche s i t e i n 1976 showing t h e ra i lway and t h e highway a t t he s i d e of t h e r i v e r . (Photo cour tesy B r i t i s h Columbia Minis t ry of Transpor ta t ion and Highways).

FRASER CANYON, B.C.

! One t r u c k d r i v e r k i l l e d

23 FEBRUARY 1949

A t ruck convoy l e f t Boston Bar l a t e on t h e a f te rnoon o f 23 February i n an at tempt t o n e g o t i a t e t h e snowbound F rase r Canyon highway south towards Vancouver. S h o r t l y be fo re 1900 h t h e convoy was stopped a t t h e Hoodoo curve by a small avalanche t h a t had been p a r t i a l l y c l e a r e d by bu l ldoze r . The d r i v e r of a t r u c k t h a t had become s tuck i n t h e depos i ted snow had begun t o mount t i r e cha ins when a l a r g e r avalanche s t r u c k . When it stopped on ly t h e roof l i n e of t h e t ruck remained v i s i b l e and t h e d r i v e r had disappeared i n t h e snow. The o t h e r d r i v e r s i n t h e convoy and t h e highway crew began a search . Another avalanche s t r u c k and engulfed f i v e o f t h e r e s c u e r s sweeping them well down t h e s l o p e towards t h e r i v e r . When t h e remaining r e s c u e r s began a s ea rch f o r t h e s e men a t h i r d avalanche s t r u c k burying s e v e r a l men t o t h e i r knees. Miraculously a l l persons were found a l i v e with t h e e x c e p t i o n o f t h e f i r s t bu r i ed d r i v e r . H i s body was loca t ed a t t h e r e a r of h i s t ruck t h e fo l lowing day.

FRASER CANYON, B.C.

One rai lway employee k i l l e d

14 JANUARY 1 95 0

Severe storms raged i n t h e Fraser Canyon e a r l y i n January 1950 causing t h r e e c losures during a three-week period. A Canadian National Railway snow plow was working south of Boston Bar on 14 January. The crew parked t h e plow 13 km south of Boston Bar and re turned nor th with t h e engine t o pick up some o t h e r equipment but t h e foreman remained with t h e plow. While t h e crew was gone an avalanche containing both snow and rock s t ruck t h e plow. I t was c a r r i e d p a r t way down t h e embankment towards t h e r i v e r , and t h e foreman was swept i n t o t h e r i v e r . When t h e crew re turned t h e foreman could n o t be found. The cause of t h e avalanche was a t t r i b u t e d t o r a i n which weakened t h e snow a t t h e canyon wal ls .

SEYMOUR INLET 27 MARCH 1955

One logger k i l l e d , one in jured

LOCATION

I Seymour I n l e t i s on t h e P a c i f i c Coast of B r i t i s h Columbia, 350 km I northwest of Vancouver and has a wet, maritime cl imate.

WEATHER

Moderate temperatures and r a i n prevai led a t t h e acc ident s i t e on 27 March. Thaw p e r s i s t e d and t h e snowpack was water-saturated.

ACCIDENT

A crew was yarding logs on a s t e e p s lope above Seymour I n l e t . On one tu rn of t h e yarder a stump r o l l e d over about 250 m upslope from t h e engine 's locat ion . During t h e next t u r n a log which was being drawn caught t h e stump and dislodged it. The stump, t h e snow surrounding it, and some of t h e su r face vegeta t ion began t o move slowly down t h e s lope , then a f t e r f a l l i n g onto s t e e p e r t e r r a i n above t h e yarder r a p i d l y increased i n volume and speed.

The signalman had c a l l e d out when t h e motion began. He himself was unable t o escape and was caught near t h e top of t h e avalanche, but a f t e r a r i d e of about 60 m was l e f t behind t h e moving snow. Two workers i n t h e landing a rea saw t h e s t a r t of t h e avalanche and ran c l e a r of it . The yarder engineer not iced it t o o l a t e , and together with t h e donkey engine was engulfed i n t h e moving snow and debr i s and swept i n t o the i n l e t . When t h e avalanche stopped t h e only th ings v i s i b l e were broken logs and o the r debr i s on t h e su r face of t h e water.

1 RESCUE

After t h e avalanche had stopped t h e unscathed workers began a surface search and found t h e signalman near t h e top of t h e avalanche path. He had sus ta ined a broken arm and cracked r i b s . H i s companions c a r r i e d him on a s t r e t c h e r from t h e slope. There was no s ign of t h e engineer , and 'cont inuing d e b r i s movement a t t h e edges of t h e avalanche path made a search d i f f i c u l t . Later searches on t h e same day revealed no s ign of t h e engineer and t h e deep water i n the i n l e t made d iv ing unfeas ib le . The body was never found. The in ju red signalman was flown by seaplane t o t h e h o s p i t a l a t Ale r t Bay.

AVALANCHE

The avalanche was triggered by the motion of the stump in the water-saturated snowpack. The loose snow avalanche started on a slope with an incline of about 10" at an elevation of about 600 m. For the first 30 m it moved slowly with a width of about 8 m. After falling over a transition onto an approximately 25" slope the avalanche quickly gained momentum and volume, and expanded to a maximum width of 120 m. The moving snow stripped the soil and vegetation down to the granite bedrock.

COMMENT

The engineer would have had to run about 50 m to safety. Probably he could have escaped if he had received a warning when the avalanche started. Unfortunately due to the noise of the engine he could hear neither a warning nor the avalanche until it was too late.

The avalanche carried the heavy logging equipment down the slope and splintered logs with diameters greater than 1 m. This illustrates the destructive force of the heavy, wet moving snow mixed with debris.

TAIL BLOCK /

X P O S I T I O N OF SIGNALMAN PRIOR TO AVALANCHE

@ P O S I T I O N OF SIGNALMAN AFTER AVALANCHE

+ P O S I T I O N OF ENGINEER P R I O R TO AVALANCHE

Figure 2 Sketch of the accident site at Seymour Inlet

-8-

WOODBURY CREEK, KASLO, B.C . 23 FEBRUARY 1957

Person on road k i l l e d

LOCAT ION

The accident s i t e i s located about 18 km south of Kaslo on the shores of Kootenay Lake.

WEATHER

Observations a t Kaslo c l imate s t a t i o n 585 m ASL

Temperature O c

Date Max Min

P r e c i p i t a t i o n

mm

20 February - 5 - 17

2 1 February -6.5 -18

22 February - 8 -15 13

23 February 5 -10.5 2 5

A storm raged from 22 t o 25 February deposi t ing deep snow i n the Nelson-Kaslo a rea .

ACCIDENT SUMMARY

The Anglican min i s t e r from New Denver drove from Nelson t o Kaslo on Saturday afternoon, 23 February. A shor t d i s t ance south of Woodbury Creek he was stopped by a small avalanche which had crossed t h e road. He got out of h i s c a r and began t o shovel a pa th through the snow. A second c a r stopped and t h e d r i v e r , a l o c a l r e s i d e n t , joined t h e min i s t e r advis ing him t o watch f o r f u r t h e r avalanches.

Suddenly a second, l a r g e r avalanche came from t h e b l u f f s above t h e road. The second d r i v e r shouted a warning and ran c l e a r of t h e avalanche's pa th , but t h e min i s t e r , running i n t h e opposi te d i r e c t i o n , was engulfed by t h e avalanche. Af te r t h e snow had s e t t l e d t h e r e was no s ign of him.

RESCUE

The second d r i v e r looking over t h e deposi ted snow was unable t o loca te the min i s t e r . He sent h i s wife, who had been wait ing i n t h e i r c a r , f o r he lp and continued t h e search . About one hour a f t e r t h e accident rescuers found t h e min i s t e r covered by 1 t o 2 m of snow, about 12 m below t h e road. No s ign of l i f e was evident . .

AVALANCHE

The storm continued and a t h i r d avalanche ran i n t h e same loca t ion on t h e following day. The f a t a l avalanche was confined t o a narrow gul ley i n s t eep , rocky b l u f f s above t h e road. The v e r t i c a l run of t h e avalanche was probably l e s s than 100 m, and a length of about 25 m of road was covered by snow up t o 2 m deep.

COMMENT

A s i n o the r cases t h e r ecur ren t na tu re o f an avalanche path proved t o be t h e cause of t h e f a t a l i t y . The min i s t e r , who served both New Denver and Kaslo, f requent ly t r a v e l l e d over t h e avalanche-prone road between t h e two towns was aware of t h e danger. H i s p recaut ions usua l ly included obta in ing advice from t h e Department o f Highways about t h e avalanche hazards before he made t h e t r i p , but he neglected t o do so on t h e day of the accident because he t r a v e l l e d over another road.

A t t h e time of t h e acc ident the road was narrow, winding along t h e shores of Kootenay Lake, and winter t r a v e l was hazardous. Since then t h e road has been re loca ted on a new, wider bench about 35 m above t h e lake . The reconst ruct ion seems t o have el iminated t h e avalanche problems a t t h i s s i t e .

McGILLIVRAY PASS, B.C. 24 MARCH 1959

Two skiers killed

McGillivray Pass is on the east side of the Pacific Coast Mountains between Anderson Lake and Bralorne, B.C. The summit, 1860 m high, is about 23 km SE of Bralorne.

WEATHER

During the week prior to 24 March 1959 approximately 45 cm of new snow accumulated in the McGillivray Pass area. March 24 was a clear, sunny day during which the temperature rose above 0°C and the top 15 cm of snow became heavy and moist.

ACCIDENT SUMMARY

I The accident itself was unobserved. At approximately 1300 h a I young Bralorne couple met a friend while skiing towards McGillivray Pass.

They intended to survey some land in the summit area, thinking of a possible purchase. Their friend, considering the new snow and the high temperature, warned them of the avalanche hazard.

Later that afternoon the friend, while skiing at Telephone Ridge on the southwest side of the valley, noted a fresh avalanche deposit on the opposite side of the valley just southeast of the pass. Ski tracks led to the deposit but none left it. When he approached the avalanche for a closer look he realized that his friends had been caught in it.

I RESCUE

The skier searched the deposition, digging and probing with ski poles at random but found nothing. He then skied back to his cabin some 3.5 km northwest of the site and telephoned to Bralorne for help.

The Royal Canadian Mounted Police in Bralorne received the report at 1745 h and gathered residents into a search party. They travelled a few miles by jeep, then by skis and snowshoes, arriving at the accident site several hours later. The rescuers searched throughout the night using scaling bars for probes and shovels for digging through the deposition. Avalanche guards had been posted to warn searchers of any further activity. On 25 March the search continued in temperatures below O"C with cloudy skies and light snowfall. At 1530 h on 25 March the first body was located; the second was located at 1035 h on 26 March. Both had died of suffocation.

The valley sides around McGillivray Pass contain numerous avalanche paths. The accident site was about 0.8 km southeast of the summit and 100 m above the valley floor on a slope with a SSW exposure, The avalanche path was approximately 50 m wide, 200 m long and its snow was deposited to a depth varying from 1.2 to 2.5 m. Deep new snowfall, followed by high temperatures and radiant heat from the sun on the southerly slope led to the unstable snow conditions.

COMMENT

The couple was evidently taking measurements of a plot of land when caught by the avalanche. Both had skiis on and were holding the opposite ends of a measuring tape. It would appear that they were so occupied that they did not consider the danger from avalanches.

TORBIT MINE, ALICE ARM, B.C. 7 APRIL 1959

One miner k i l l e d

WEATHER

Observations a t Torbi t S i l v e r Mine, 300 m ASL

Temperature P r e c i p i t a t i o n O C

Date Max Min mm

3 Apri l 6.5 0 2 3

4 Apri l 6.5 1 . O 9

5 Apri l 6.0 0 1.5

6 Apri l 7.0 -1.5

7 Apri l 8 .O -0.5

In March a t o t a l snowfall of 3.6 m accompanied by some r a i n was reported. On 7 Apri l t h e temperature was above O°C and t h e snow was melting.

ACCIDENT SUMMARY

The su r face rai lway a t t h e Torbi t S i l v e r Mine extended f o r about 800 m along t h e s i d e of a s t e e p mountain between t h e mine and t h e m i l l . The e n t i r e length of t r a c k was covered by a snow shed.

On 7 Apri l a t about 1300 h t h e t r a i n crew made t h e second t r i p of the day from t h e m i l l t o t h e mine. The switchman rode t h e f i r s t of f i v e empty c a r s and t h e motorman t h e engine a t t h e r e a r . When t h e t r a i n approached t h e mine an avalanche s t ruck , broke t h e shed around the f i r s t two c a r s and buried t h e switchman i n t h e debr i s .

RESCUE

After at tempting, without success, t o r eve r se t h e t r a i n t h e motorman and o the r he lpe r s began t o c l e a r t h e debr i s around t h e lead c a r . Af ter about twenty minutes t h e switchman was uncovered but showed no s igns of l i f e . Attempts t o revive t h e v ic t im were unsuccessful .

AVALANCHE

The avalanche contained wet snow mixed with rock and appeared t o be t h e r e s u l t of high temperatures and snowmelt. I t ran over a width of about 30 m and deposited d e b r i s t o a maximum depth o f 5 m i n t h e snow shed. About 12 m of snow shed was destroyed.

COMMENT

A previous avalanche had occurred a t t h e same s i t e i n March 1959 and another one e igh t years before t h a t . The weight of t h e snowfall deposi ted on the shed appeared t o have been a problem, and t h e removal of t h i s snow was o f greater concern t o t h e mine management than avalanches. The snow was probably a l r eady so heavy t h a t l i t t l e add i t iona l weight from t h e avalanche was requi red t o break t h e shed.

REFERENCE

B r i t i s h Columbia Department of Mines and Petroleum Resources; Annual Report 1959; Vic tor ia , B.C.

MT. GARIBALDI, SQUAMISH, B.C. 19 JULY 1961

One climber killed, one injured

WEATHER

Temperatures ranged from 12 to 2S0c at Squamish during the week prior to 19 July. Precipitation of 3 mm was recorded on 16 July.

ACCIDENT

Three climbers left Vancouver 18 July intending to spend three days climbing in the Mt. Garibaldi area. When they arrived in Garibaldi Park they were told by work crews that it had not been cold enough at night for the snow to consolidate properly. Because of this the group decided to climb in the early morning hours. At approximately 0500 h the party was caught in an avalanche about 250 m below the Saddle Peak of Mt. Garibaldi. Two were injured, one severely, and the third was unhurt.

RESCUE

About one hour after the accident the unhurt climber left to summon help. At about 1100 h on the Diamond Head road he met a Provincial Parks employee who drove him to the police station in Squamish. The Royal Canadian Mounted Police notified the Air Force Search and Rescue Group at Comox who in turn dispatched a helicopter for an aerial search.

At around 1600 h a second member of the party was noticed scrambling down the slopes below the accident site. He was picked up and flown to the Diamond Head Lodge. He was, however, unable to pinpoint the third person's location. The helicopter crew finally located the avalanche and the third member of the party but was unable to land there. A ground crew was organized and dropped about one hour's hike from the accident site. At 2240 h the rescue group, on foot, reached the victim who had died from severe chest injuries.

COMMENT

The climbers had essentially the right idea, to complete the climb early in the morning. Unfortunately they had not realized that the night temperature had not dropped low enough for the wet snow to stabilize, therefore that avalanche hazard can be high after a warm night.

SILVER STAR SKI AREA, VERNON, B.C.

One s k i e r k i l l e d

21 JANUARY 1962

WEATHER

Observat ions a t Vernon BX c l ima te s t a t i o n , ' 5 1 6 m ASL

Temperature P r e c i p i t a t i o n . O c

Date Max Min mm

17 January -10 -15 N i 1

18 January - 15 -19.5 N i 1

19 January - 16 -19.5 , Trace

20 January -15 -25.5 N i 1

2 1 January -14 -25.5 N i 1 \, i

Between 13 and 16 January 13.7 mm of p r e c i p i t a t i o n was recorded a t Vernon BX s t a t i o n .

ACCIDENT

S h o r t l y be fo re noon on 21 January a l o c a l s k i r a c e r decided t o s e t a downhill course on S i l v e r S t a r mountain. Together wi th a younger companion he gathered a few s la lom p o l e s and s t a r t e d from t h e t o p of t h e pomal i f t . A s h o r t d i s t a n c e beyond t h e second g a t e t h e younger s k i e r f e l l , and h i s harnesses r e l e a s e d . The o t h e r s k i e r cont inued t o s e t t h e t h i r d g a t e while h i s companion remained behind t o f i x h i s s k i s . When t h e young s k i e r was mobile aga in he sk i ed t o t h e t h i r d g a t e but found no s i g n of h i s f r i e n d , on ly t h e g a t e p o l e s and a "break" i n t h e snow nearby. Thinking noth ing o f t h e "break1' ( f r a c t u r e ) he cont inued s k i i n g down assuming t h a t h i s f r i e n d had l e f t .

Another s k i e r r e s t i n g a t t h e c h a l e t n o t i c e d an avalanche j u s t be fo re 1200 h but d i d no t t h i n k t h a t anyone might be t rapped i n i t . A t 1310 h he ascended p a r t way up t h e pomal i f t t hen t r a v e r s e d t h e s lope towards t h e avalanche looking u p h i l l f o r f u r t h e r p o t e n t i a l ava lanches . When he sk i ed t o a p o i n t below t h e avalanche depos i t i on he no t i ced a

p a i r of s k i i s ly ing on t h e surface i n t h e midst o f t h e avalanche deposi t ion about 60 m above him.

RESCUE

The person who discovered t h e s k i s on t h e avalanche r e a l i z e d t h a t some one could be buried t h e r e . He skied t o t h e bottom of t h e h i l l , a l e r t e d t h e s k i p a t r o l , then mounted t h e l i f t and re turned t o t h e s i t e . He f e l t it would be f a s t e r t o r i d e t h e l i f t than t o climb t h e 60 m u p h i l l f o r an inspect ion . A s k i i n s t r u c t o r , experienced i n avalanche rescue and a l e r t e d by t h e s k i p a t r o l gathered volunteers and some long s t i c k s f o r probing.

The f i r s t rescuer t o a r r i v e on t h e s i t e discovered t h e v ic t im ' s boots and one arm prot ruding from t h e snow. Digging by hand proved unsuccessful , only shovels could pene t ra te t h e hard, chunky snow t o t h e v ic t im ' s head approximately 75 cm below t h e su r face . The rescuers attempted a r t i f i c i a l r e s p i r a t i o n , but were unsuccessful i n t h e i r at tempts t o revive t h e v ic t im. A doctor ordered t h e rescuers t o remove the v ic t im by toboggan t o t h e s k i p a t r o l shack where he was pronounced dead due t o su f foca t ion .

AVALANCHE

The avalanche, which f rac tu red j u s t below t h e t h i r d downhill ga te , was t r i g g e r e d by t h e s k i e r . The s l a b f r a c t u r e occurred i n wind c rus ted snow and va r i ed i n depth from 30 t o 75 cm. The s t a r t i n g zone, which had a gradient varying from 30' t o 3 S 0 , held a SSE aspect with ground surface of mixed scrub vegeta t ion and broken s h a l e . The avalanche ran a d i s t ance of 220 m and was 15 m wide. I t deposi ted snow t o a maximum depth of 1.2 m . The deposi t ion was described a s being a combination of hardpacked snow and l a rge angular chunks.

COMMENT

The vic t im was a l o c a l r a c e r and a member o f t h e volunteer s k i p a t r o l . He s e t t h e t h i r d ga te i n a flagged non-skiing a rea of t h e mountain, where t h e snowpack was probably r a r e l y d is turbed and the re fo re prone t o deep i n s t a b i l i t y . Avalanches a r e r a r e a t t h e S i l v e r S t a r Ski Area and it i s not s u r p r i s i n g t h a t t h e v ic t im ' s companion thought nothing of t h e "breaks" he saw i n t h e snow near t h e ga te .

Af ter t h e accident some bulldozer work was done i n t h e gu l ly with t h e expecta t ion of reducing t h e hazard, but avalanche condi t ions s t i l l develop on an inf requent b a s i s .

SKI TRACK OF V I C T I M ,

PREVAILING

ROAD

0

ROCKY I \

DEEPEST FRACTURE

LARGE CHUNKS "\ \ I N DEPOSITION

LOCATION OF BURIED BODY

Figure 3 Sketch of the accident site, Silver Star Ski Area

OCEAN FALLS, B.C. 13 JANUARY 1965

Seven r e s i d e n t s k i l l e d , f i v e in ju red , seve ra l bui ld ings destroyed

LOCAT I ON

The town of Ocean F a l l s i s a t sea l e v e l on t h e Pac i f i c Coast about 500 km northwest of Vancouver, B . C . The c l imate i s very wet with a mean annual p r e c i p i t a t i o n of 4400 mm.

WEATHER

Observations a t Ocean F a l l s Townsite 5 m ASL

Temperature P r e c i p i t a t i o n O C

Date Max Min mm

9 January 1 -5 10

10 January 1.5 - 3 16

11 January 1.5 0.5 3 4

12 January 3.5 0.5 2 1

13 January 5.5 1 133

Between 31 December and 8 January 136 cm of new snow was recorded a t Ocean F a l l s . Extremely heavy r a i n f e l l a t the townsite on 13 January.

ACCIDENT SUMMARY

The t h r e a t of f looding and s l i d e s became prevalent a s heavy r a i n f a l l continued during t h e evening of 13 January. A t 2030 h t h e western end of the ground f l o o r a t t"I'he Willowstt apartments was flooded by s lush and water . The Royal Canadian Mounted Pol ice a s s i s t e d t h e t enan t s t o evacuate t h e bui ld ing. Because of t h e increas ing avalanche hazard t h e Pol ice a l s o decided t o c l o s e t h e road between t h e townsite and Martin Valley, a subdivision 1.5 km west of t h e town. A t approximately 2130 h power and telephone communications were i n t e r r u p t e d .

At 2200 h an avalanche came down a gully from Mt. Caro Marion carrying trees, mud and boulders. At the lower end of the gully it separated into three arms, two of them followed watercourses on the alluvial fan. The arm in the westerly creek destroyed half a duplex house above Burma Road, knocked down the porch of a second duplex and finally demolished the end rooms on a bunkhouse at the water's edge. The easterly arm struck and completely destroyed another duplex above Burma Road, carried the wreckage downhill and struck the print shop and Credit Union buildings below. Both were destroyed and two adjacent buildings were partially damaged. The wooden roadbed of Burma Road was also torn out by the avalanches.

Three of the seven persons residing in the western duplex were trapped in the undestroyed portion of the home. The other four persons and the three persons residing in the eastern duplex were engulfed by the avalanche.

RESCUE

Police officers and volunteer rescuers were working at the Willows Apartments just east of the accident site when the destructive avalanche occurred. The rescuers immediately began a search of the avalanche debris, freed the three trapped persons, and recovered two bodies within one-half hour after the avalanche. The injured persons were evacuated to the town hospital where an emergency power system had been set up. The paper mill was shut down when news of the disaster was received, and the workers joined the rescue parties. The townspeople living around the avalanche area were advised to leave their homes and take refuge at the hotel or the mill. Those residents in areas cut off by the slide were evacuated to safe positions by boat. At 0200 h on 14 January another avalanche which ran down between the two earlier tongues occurred. Rescue efforts were called off until dawn.

The ship Northland Prince arrived on its regular run at 0430 h and stayed in port until the damage and further potential danger could be assessed. At dawn the rescue effort was renewed. It was extremely slow going because of the mixed snow, mud, rock, and wrecked timbers. The long-distance telephone communication was reestablished at 0700 h.

The search continued for several days until the last two bodies were recovered 19 January. In all seven persons were killed and five injured . AVALANCHE

Mt. Caro Marion rises to an elevation of 1234 m above the Ocean Falls townsite. The avalanche path in question starts at an elevation of approximately 915 m on the south slope of the mountain and runs over much of its vertical fall in a rock canyon approximately 25 m wide. The average gradient in the canyon is approximately 45'. The avalanche of 13 January started in the canyon between 400 and 500 m elevation. The

canyon opens into an alluvial fan over a talus slope at approximately 120 m elevation.

The avalanche was the result of heavy snowfalls in early January followed by high temperatures and heavy rain on 13 January. Local residents mentioned a freezing rain in December which coated the town with ice. The ice layer, when lubricated by the rain, might have provided an initial sliding surface for the deep snow. The avalanche was probably triggered by wet snow sluffing from the canyon walls, and once in motion collecting additional wet snow, mud, boulders, and trees.

Several other avalanches ran on Mount Caro Marion during the same night, but caused no damage other than blocking the road to Martin Valley in four places.

COMMENTS

The avalanche 13 January 1965 was an unusual occurrence caused by a combination of adverse weather factors. Such avalanches might only be observed once in 50 to 100 years. The older residents of Ocean Falls could not remember avalanches reaching the townsite before. The only large avalanches in memory were two of mixed snow and mud that crossed the Martin Valley road 2 December 1957. That day 216 mm of rainfall was recorded.

This case illustrates the need for zoning studies before a subdivision is built. The avalanche tracks above the residential areas can easily be recognized, and from studies of the terrain, the tree growth, past avalanche activity, and calculations of the theoretical runout distance the extent of any possible large avalanche could have been determined. Either no buildings should have been placed in the dangerous zone or defences should have been provided for their protection.

After the accident small dikes were bulldozed along the track of the destructive avalanche, but they were no longer evident in 1978.

Figure 4 Mount Caro Marion and townsi te with t h e avalanche t r a c k i n t h e c e n t r e

- 2 2 -

ROCK CANYON Y\ MATURE TIMBER; SLOPE INCLINE 30" MATURE TIMBER;

SLOPE INCLINE 30"

COUS I NS I NLET

Figure 5 Sketch map of t h e accident s i t e showing t h e extent of t h e avalanches

MT. ST. ELIAS, YUKON TERRITORY 11 AUGUST 1971

Four climbers killed

On 11 August, after completing ascents on Mt. Logan, five members of an expedition party attempted an ascent of Mt. St. Elias from the Newton Glacier via Russel Col, the original route climbed by the Duke of Abruzzi at the turn of the century.

WEATHER

During the afternoon o$ 11 August the temperature was above 0°C and it was sunny although the NE face of St. Elias was in the shade. The climbers had observed extensive avalanche activity on the south-facing slopes of Mts. Newton and Jeannette but not on St. Elias or Russel Col. There was, however, evidence of old avalanche tracks and depositions on these slopes.

ACCIDENT

At approximately 1600 h the climbers, travelling on two ropes, were about 90 m above the Newton Glacier on the 750 m high slope leading to Russel Col. Hearing a loud crack the climbers looked up and saw an avalanche coming off the NE face of Mt. St. Elias and spreading across the slope above them. The group attempted to dig in, but the entire party was swept away within 5 or 6 seconds. When the avalanche had stopped only one climber (who was on the lead rope) and a stuffsack remained on the surface.

RESCUE

After unsuccessfully attempting to pull up the buried rope and to dig with his hands, the survivor, in a state of shock, headed back down the route without pack, snowshoes, or ice axe. He collected some food from the party's cache on the Newton Glacier, as well as from the caches of other expeditions, and headed for the main cache on the Seward Glacier. After spending the night on Newton Glacier he arrived at the Seward Glacier cache late on 12 August and radioed the Arctic Institute of North America station at Kluane Lake. The following day he was picked up by helicopter and flown to Kluane Lake. The bodies of the other climbers were not retrieved because of their remote location and the hazardous conditions.

AVALANCHE DATA

The avalanche was initiated by glacial ice blocks breaking off the steep slopes to the south of Russel Col at approximately the 3400 m

l e v e l . As l a r g e amounts of wet snow were picked up dur ing t h e motion of t h e avalanche, i t cons i s t ed o f mixed wet snow and i c e blocks. The depos i t i on , which s e t t l e d and hardened very quick ly , was 60 m wide, 20 m long, and 2 t o 3 m deep.

COMMENT

The su rv ivo r f e l t t h a t t h e p a r t y should have recognized t h e avalanche danger i n view of t h e o l d d e p o s i t s and cu r ren t a c t i v i t y , bu t t h e absence of any avalanches running nea r t h e climbing r o u t e on t h a t p a r t i c u l a r day made t h e cl imbers f e e l conf ident .

REFERENCE

American Alpine Club and Alpine Club o f Canada; Accidents i n North American Mountaineering, 1971.

Y - , ( HALL PARTY )

Figure 6 Map of s c a l e 1:250,000

NINE MILE MTN., near HAZELTON, B . C .

One snowmobile ope ra to r k i l l e d

WEATHER

Observat ions a t New Hazelton c l ima te s t a t i o n . 313 m ASL

Temperature " C

P r e c i p i t a t i o n

Date Max Min mm

10 March 5.5 0 .5 3.0

11 March 7.0 0 Trace

12 March 6 .0 -0.5

13 March 6.0 -5.5

14 March 8.5 -1.0

Several days of f reeze-thaw had been experienced a t Nine Mile Mountain. On 14 March t h e snow s u r f a c e was f i rm i n t h e d rea .

ACCIDENT SUMMARY

A p a r t y on s i x snowmobiles l e f t Hazelton 14 March t o spend t h e day a t a cabin on Nine Mile Mtn., approximately 10 km nor theas t o f Hazelton. The group t r a v e l l e d p a r a l l e l t o Two Mile Creek then ascended by road t o t h e cabin a t t h e 1475 m l e v e l . In t h e a f te rnoon they decided t o s o r t i e n o r t h along t h e west f ac ing s lope a t Nine Mile Mountain .

Two snowmobiles were leading a climbing t r a v e r s e below t h e r i d g e , one s l i g h t l y ahead and above t h e o t h e r . Suddenly t h e second d r i v e r no t i ced snow washing up aga ins t h i s machine and looking ahead saw t h a t t h e o t h e r v e h i c l e was a l s o being washed by avalanching snow. The lead d r i v e r was running along on t h e u p h i l l s i d e of h i s machine, presumably t r y i n g t o prevent it from r o l l i n g over . Rea l iz ing what was happening t h e second d r i v e r opened h i s t h r o t t l e and turned downhill with t h e avalanche. Af t e r momentarily l o s i n g consciousness he found himself

s i t t i n g with h i s machine a few metres from t h e edge of t h e avalanche deposi t ion . There was no evidence of t h e lead machine. The time was approximately 1600 h.

RESCUE

The second d r i v e r immediately proceeded t o a spot i n t h e avalanche deposi t about 25 m away, near t h e base of some small t r e e s , and began t o d ig . A few moments l a t e r t h e o t h e r four d r i v e r s , who had been wait ing i n t h e saddle near t h e cabin, a r r ived . Asked why he was digging i n t h a t p a r t i c u l a r spot t h e second d r i v e r could only answer t h a t he knew t h e v ic t im was t h e r e . One machine returned t o t h e cabin f o r shovels and f i r s t a i d equipment.

I

J u s t a s t h a t machine re turned t h e second d r i v e r located t h e s k i of h i s companion's machine about 1.5 m below t h e surface . The group continued digging with shovels and found t h e v ic t im face up, blue and not brea th ing, underneath t h e overturned snowmobile 2 . 2 t o 3 m below the snow surface . Approximately 40 minutes had elapsed s ince t h e accident occurred. Removing t h e v ic t im from t h e hole was very d i f f i c u l t because t h e snow had s e t l i k e cement. A t r a i n e d f i r s t a i d man i n t h e group attempted cardio-pulmonary r e s u c i t a t i o n but t o no a v a i l . The body was taken t o Hazelton on a first a i d toboggan t h a t had been s tored a t t h e cabin .

I AVALANCHE

The l a rge dry snow avalanche conta in ing both a s l a b and a broken cornice was probably t r i g g e r e d by t h e passage of t h e snowmobiles. The f r a c t u r e l i n e had a maximum depth of 4 m, and t h e avalanche ran on o r near t h e ground. Wind during t h e winter had scoured t h e r idge and deposi ted t h e snow on t h e avalanche slope. The major i ty of t h e avalanche snow, both chunky and f i n e i n t e x t u r e , was deposi ted a t t h e s lope t r a n s i t i o n .

I COMMENT

The s lope i n quest ion was f a i r l y s h o r t and was described by t h e survivors a s not being p a r t i c u l a r l y s teep . I t was s t e e p enough, however, t o s u s t a i n some cornice development along t h e r idge , a s u r e s ign o f p o t e n t i a l avalanche hazard. The group found t h e snow sur face f i rm enough t o allow walking, but perhaps a snowpit observation would have revealed deep i n s t a b i l i t y .

Eye witness observations about the v i c t i m ' s l a s t seen po in t , and any su r face c lues a r e c r i t i c a l i n loca t ing r a p i d l y buried persons. In t h e present case t h e second d r i v e r must have subconsciously recorded the loca t ion where t h e f i r s t d r i v e r disappeared which l ed him immediately t o t h e c o r r e c t spot .

N- ALMOST NO DEFINED FRACTURE

FRACTURE APPROX 4 m AND CORNICE BREAK

APPROX 300 m

+ LAST SEEN POINT OF THE V I C T I M

@ LOCATION OF THE BURIED V I C T I M

X LOCATION OF THE SECOND DRIVER WHEN THE AVALANCHE STARTED

@ LOCATION OF THE SECOND DRIVER AFTER THE AVALANCHE --- PATH OF THE SNOWMOBILE

Figure 7 Sketch of the accident site Nine Mile Mountain

WESTCASTLE SKI AREA, ALBERTA

One machine damaged, operator injured

13 FEBRUARY 1975

WEATHER

Observations taken at Westcastle Day Lodge, 1415 m ASL

Temperature Precipitation Snow Foot Wind "C Depth Penetration (est . )

New Storm Snow Snow

Date Time Max Min cm cm cm cm

9 February p.m. 14

10 February 0630 0 -15 13 no obs. 113 55 light S 1830 -4 -19 12 33 119 5 8 light - m0d.N

11 February 0640 -19 -22 6 3 7 122 62 mod. NW 1945 -20.5 -22 2 2 5 7 138 78 light N

12 February 0630 -21 - 2 2 16 no obs. 152 78 calm 1945 -18.5 -22.5 39 93 175 120 light - mod.SW

13 February 0630 0 - 16 6 8 6 164 no obs. light - mod.NW 1825 1 -14 9 85 162 107 mod. NW

At approximately 2000 h on 12 February a warm air mass, which had earlier enveloped the upper mountain, sank to the Day Lodge at the base of the ski area causing the temperature to rise 13.S°Cin a few minutes. On 12 and 13 February observers at the top lift station reported moderate and gusting winds from the southwest.

A snowprofile taken 9 February at the top of Shotgun Gulch (1800 m elevation, ENE aspect) revealed 50 cm of temperature-gradient snow near the ground, overlain by 1 m of equitemperature snow and partially settled new snow at the snow surface.

AVALANCHE OBSERVATIONS

10 February Explosive control produced numerous avalanches and extensive settlement.

11 February Controlled avalanches on N, NE, and E exposed slopes (including Shotgun Gulch).

12 February Controlled small avalanches on N, E slopes; one 25 cm deep fracture on NE exposure.

ACCIDENT SUMMARY

In mid-February 1975 the Canada Winter Games were held at Westcastle Ski Area. A storm began 9 February and by 12 February a large amount of new snow had accumulated. The visibility at the avalauncher gun at the top of the T-bar lift station was limited to 200 m. Due to the poor visibility and an expectedly high number of unexploded projectiles, the avalauncher gunner did not want to fire blindly. Control by hand charges along an alpine route was attempted but was abandoned because of the avalanche hazard and poor visibility.

On the morning of 13 February the visibility had improved although Chinook conditions prevailed in the alpine region. At 0730 h the avalanche control team noted an abrupt temperature increase while ascending the T-bar lift. The first avalauncher shot was fired into the south side of the North Cirque and released a large avalanche which ran down Shotgun Gulch to the Bunny Hill (Figure 8). A second shot was fired into the north side of the North Cirque resulting in a second, larger avalanche that destroyed the old upper lift base then moved down Shotgun Gulch, crossed the Bunny Hill, and struck a grader on the road below. The force of that avalanche blew out the windows of the grader and snow pinned the operator against his seat.

RESCUE

Only about 50 cm of snow was deposited around the grader wheels so rescue workers were able to free the operator from the cab then drive the grader clear of the avalanche path. The grader operator was taken to the hospital with minor injuries. A helicopter parked on a temporary pad just below the road was not affected by the avalanche.

AVALANCHE DATA

Both avalanches of 13 February ran on a lubricating layer of 15 cm of light dry snow which was deposited at the beginning of the storm. ,

The second avalanche started at an elevation of approximately 2050 m and ran out at an elevation of approximately 1400 m. The first fracture occurred on a slope with an ENE aspect and the second on an ESE slope.

COMMENT

It should not happen that a vehicle be in the path of avalanches that are released by gunfire. This accident occurred because of lack of communication between the avalanche control team and the grader operator. Strict control of traffic, including private vehicles, maintenance equipment, and skiers is an essential part of avalanche control by explosives. The measures include radio contact between the control personnel, road blocks, and maintenance vehicles.

The avalanche control team at the Westcastle Ski Area did not expect the second avalanche to be as large as it was. In theory the first avalanche, starting at a leeward slope and picking up unstable snow in the track, should have had a greater volume than the second, but the snowfall, together with high temperatures and a moderate wind of variable direction appeared to have deposited deep, rather cohesive snow at the Northside of the Cirque, and this snow fractured over a wide area.

One of the objectives of control by gunfire is to release small avalanches through repeated firings during snow storms and thus prevent the formation of large, destructive avalanches. Unfortunately the old model avalauncher was unreliable for blind firing and the snow could not be released continuously in small amounts.

SECOND AVALANCHE

Fl RST AVALANCHE

-N

SHOTGUN GULCH

ROAD

Figure 8 Sketch of the avalanche path

Figure 9 Map 1:50,000 with fracture of the avalanches

MT. FISHER, near CRANBROOK, B.C. 11 J U N E 1976

Three mountain cl imbers in ju red

WEATHER

The sky was c l e a r and t h e temperature average during t h e week p r i o r t o 11 June. The fo recas t predic ted t h e same weather would continue, however between 1130 and 1200 h on 11 June a warm a i r mass s t ruck t h e a rea .

ACCIDENT SUMMARY

Three cl imbers l e f t a logging road on Boulder Creek a t 0630 h f o r a climb on t h e North Face of M t . Fisher , 2838 m e l eva t ion , over a mixed snow, i c e and rock route . Between 1130 and 1200 h while cramponing i n a snow cou lo i r some 180 m below t h e peak, t h e group not iced a change i n t h e weather. The temperature began t o r i s e , mists began t o r o l l over t h e peak, and t h e snow began t o so f t en . About one-half hour l a t e r t h e climbers reached the t o p of t h e cou lo i r where they removed t h e i r crampons i n a n t i c i p a t i o n of a s s a u l t i n g t h e f i n a l 60 m of rock.

Af ter some discuss ion t h e cl imbers decided t h a t i n view of the increas ing avalanche hazard they should descend r a t h e r than continue. Descending through t h e c o u l o i r t h e group reached an open snow slope and stopped t o d iscuss t h e i r next move. The opt ions were e i t h e r t o wait f o r a freeze-up o r t o c ross t h e snow slope. Choosing t h e l a t t e r they t r ave r sed t h e snow slope with two ropes joined, belaying from a sa fe p o s i t i o n . The ropes were not q u i t e long enough f o r t h e lead climber t o reach a s a f e spot before t h e middle climber had t o advance even though t h e lead climber was s t i l l moving. The lead climber had j u s t reached the f a r s i d e of t h e snow f i e l d and was i n t h e process of p u t t i n g i n a f i rm belay, when t h e middle man, a f u l l rope length behind, was h i t by a small , f a s t avalanche and c a r r i e d downslope. The lead c l imber ' s be lay held t h e middleman, but t h e t h i r d climber was pul led out of h i s i c e axe belay and f e l l onto rock and snow below. The rope between the lead and t h e middle climber then broke and t h e middle and t h i r d climbers continued t h e i r f a l l . When they came t o r e s t t h e two men were s t i l l roped toge the r , were su f fe r ing from various i n j u r i e s , and t h e i r helmets were badly damaged.

RESCUE

After regain ing t h e i r w i t s t h e two cl imbers decided t o p a r t . One would climb with a l l t h e spare c lo th ing t o t h e person above, who had c a l l e d down saying she was h u r t , while t h e o the r would go f o r help. The time was about 1400 h. The descending climber reached a house a t 1800 h

and telephoned t h e Royal Canadian Mounted Pol ice reques t ing a h e l i c o p t e r . The h e l i c o p t e r a r r ived s h o r t l y a f t e r 2000 h , picked up t h e climber and flew with him over t h e acc ident s i t e where t h e two remaining climbers could be seen digging a snow cave. The h e l i c o p t e r then picked up t h r e e f r i e n d s i n t h e v a l l e y who had overnight equipment and dropped them a t t h e base of t h e mountain j u s t a s darkness f e l l , about 2230 h . They reached t h e accident s i t e a t about 0100 h , j u s t before r a i n began t o f a l l .

A t f i r s t l i g h t on 12 June a he l i - r e scue team a r r i v e d from Banff, and a t 0600 h t h e r e scuers , s lung below t h e h e l i c o p t e r , brought out t h e in ju red v ic t ims and t h e rescue pa r ty . By 0800 h t h e rescuers were evacuated t o Fort S t e e l e and t h e v ic t ims t o Cranbrook Hospital .

AVALANCHE

The two cl imbers f e l l a t o t a l d i s t a n c e of about 450 m from an e leva t ion of approximately 2400 m. The small wet avalanche caught t h e climbers on a nor th fac ing s lope inc l ined a t about SO0.

COMMENT

If t h e cl imbers had turned back a s soon a s t h e weather began t o change they might have escaped t h e acc ident . Af ter t h e acc ident they r e a l i z e d t h a t they had ignored a t h i r d option t o avoid t h e uns table snowfield, i . e . , t o descend d i r e c t l y from t h e c o u l o i r t o an i c e c l i f f t h a t they had ascended e a r l i e r and rappel from it t o s a f e r s lopes below. Being caught by the avalanche was bad luck but t o survive t h e 450 m f a l l was fo r tuna te indeed. The cl imbers f e l t t h a t without helmets they would not have had a chance f o r su rv iva l .

SUNSHINE VILLAGE, BANFF NATIONAL PARK, ALBERTA 11 DECEMBER 1976

One skier buried

WEATHER

Observations at Sunshine studv lot 2145 m ASL

Temperature New Precipitation Snow Wind O C Snow Depth

Date Time Max Min cm mm cm km/h

7 December 0800 -6 -10 4 2 4 5 S 23 1500 -4 - 7 1 1 46 SE 23

8 December 0800 -2 -5 5 6.5 48 S 32 1500 -2 -3 Trace Trace 48 S 29

9 December 0800 -2 -19 19 12 6 4 S 16 1500 -9 -11 1 Trace 65 S 7

10 December 0800 -9 -16 1 1 5 8 S 30 1500 -6 -10 3 2 57 SE 27

11 December 0800 -5 - 7 7 7 62 S 32 1500 -4 - 6 7 3 69 S 10

Strong southerly winds were recorded at the Sunshine study plot between 1000 h 10 December and 1000 h 11 December. December 11th was the first day of operation of the ski area and only a limited number of runs were open to the public. Virtually no consolidation had taken place in the snowpack at this time.

ACCIDENT SUMMARY

Three skiers attempted to ski the closed "Bunker's Run" from the top of the Standish Chair Lift. After being informed by the lift operator that the area was closed, they skied in the direction of Jerry's Run, but a short distance down the hill they ducked under the rope fence, passed a "No Skiing" sign, and entered Bunker's Run. The group then proceeded to the Donkey's Tail, and in doing so passed several boundary poles and a sign

t h a t read "Danger, Avalanche Area, Closed". Enroute they t r iggered a small avalanche i n t h e Standish Face a rea .

A t t h e Donkey's T a i l t h e group s t a r t e d t o s k i down. The f i r s t s k i e r s a f e l y reached t h e bottom of t h e s lope but t h e second s k i e r f e l l about mid-slope. A s t h e t h i r d s k i e r entered t h e top o f t h e slope an avalanche re leased t h a t c a r r i e d t h e f a l l e n s k i e r down and bur ied him a t t h e t r a n s i t i o n of the s lope . The f i r s t and t h i r d s k i e r s escaped b u r i a l . The time was 1000 h.

RESCUE

A group of s k i i n s t r u c t o r s who had witnessed t h e acc ident went t o t h e s i t e immediately. The avalanche and t h e r eac t ion of t h e s k i i n s t r u c t o r s were observed from t h e s k i l i f t and repor ted t o t h e Parks wardens who l e f t t h e bottom of t h e l i f t by snowmobile with equipment f o r a has ty search a t 1010 h . Meanwhile t h e s k i i n s t r u c t o r s had made a surface search , marked t h e l a s t - seen p o i n t , and formed a probel ine a t t h e bottom of the deposi t ion using upturned s k i poles.

A t approximately 1007 h one of t h e survivors located t h e bur ied s k i e r who was blue i n t h e f ace and not brea th ing. A rescuer began t o administer a r t i f i c i a l r e s p i r a t i o n and t h e v ic t im responded immediately. A t 1015 h t h e park wardens and t h e s k i p a t r o l a r r i v e d , placed t h e v ic t im on a f r a c t u r e board, and removed him with a toboggan t o a wait ing ambulance.

AVALANCHE DATA

The avalanche, t r igge red by t h e s k i e r s , ran on t h e ground i n an uns table base of depth hoar. The s l a b f r a c t u r e d with a depth of 70 cm, and a width of about 15 m, and ran about 45 m v e r t i c a l l y . The s lope had a NE a spec t , was i n t h e l e e of t h e p reva i l ing wind, and was inc l ined approximately 40° i n the s t a r t i n g zone.

COMMENT

Signs reading "High Avalanche Danger" and "Only J e r r y ' s Run Open" were placed a t the bottom of Standish Chair L i f t . The group of s k i e r s consciously v i o l a t e d t h e c losures and came very c l o s e t o a t ragedy.

The s k i i n s t r u c t o r s had r e c e n t l y p rac t i ced avalanche rescue techniques and knew how t o i n i t i a t e an organized search immediately. This emphasizes t h e value of teaching avalanche awareness and rescue techniques t o s k i a rea s t a f f and i n s t r u c t o r s who work i n a reas with avalanche problems.

E w E

T E M P E R A T U R E , "C E 0- U * U UY

w- y -> C

I I - I I I I N a 5: Z c- z * Lu

I n Z m 3 U >

w e I

- 1 2 -10 -8 - 6 - 4 - 2 W E , - z z L E - I Q a o 2 I E E m a U

a CI

X A I R T E M P . - 60

- - 50

- X 40 I + I \ 1 I - - 30

0 4, 1 TO 2 0.14 \ - \x, \

- 20 < - '. - A 4 + 0.18 , 10 X.. . ' . . -

Figure 10 Snow profile of 6 December at Sunshine Village study plot 2145 m ASL

Figure 11 View of t h e avalanche s i t e (Photograph cour tesy Parks Canada) Key : + Victims l a s t seen po in t @ Location of bur ied v i c t im x Third member of t h e p a r t y

CHANCELLOR PEAK, YOHO NATIONAL PARK, B.C.

Three mountain climbers killed

12 DECEMBER 1976

WEATHER

Observations at Westgate Yoho National Park 1065 m ASL

Temperature New Snow O C Snow Depth

Date Max Min cm cm

8 December, AM 1 PM 3

9 December, AM PM

10 December, AM - 4 - 12 12 PM - 1 - 6 T

11 December, AM + 1 PM + 2

12 December, AM - 2 -13 PM - 2 -12

On 12 December the wind was calm and the sky cloudy.

ACCIDENT SUMMARY

On the morning of 12 December three climbers registered with the Parks authorities intending to climb the NW ridge of Chancellor Peak and return the next day. The trip was considered a training climb for the two youngest members of the team. Departing from Hoodoo Creek campground (12 miles west of Field on Highway 1) the group climbed to the 2500 m level. Tracks indicated that the climbers descended from this point into a gullied, avalanche prone area on the west face, where they appeared to have done some practice climbing. When they returned to the ridge they were caught in an avalanche at the 2400 m level, carried over steep rocky terrain and buried at the 1850 m level.

RESCUE

A morning check of t h e r e g i s t r a t i o n book 13 December indica ted t h a t t h e p a r t y was due a t 1100 h. Between 1100 and 1200 h t h e parks s t a f f received a c a l l from a concerned family member s t a t i n g t h a t t h e cl imbers had not ye t returned.

Af ter a check a t Hoodoo Creek campground revealed no s ign of t h e group's r e t u r n the park wardens i n i t i a t e d a ground search a t 1300 h . A t 1335 h a h e l i c o p t e r was c a l l e d f o r from Banff toge the r with a t r ack ing dog and dog master. An a e r i a l search along t h e foo t t r a c k s of t h e missing p a r t y led t o t h e discovery of a r ecen t avalanche and of o b j e c t s on t h e surface of t h e depos i t . A t 1545 h park wardens landing on t h e s i t e with t h e a i d of a s l i n g beneath t h e h e l i c o p t e r found c lo th ing and a packsack on t h e deposi t . A t 1550 h t h e f i r s t v ic t im was located under 0.4 m of snow. The rescuers followed t h e climbing rope a t tached t o t h e body and a t 1615 h found t h e second vic t im 0.6 m below t h e snow surface and t h e t h i r d one buried 1.2 m deep. A l l were dead when discovered. By 1645 t h e bodies and t h e rescue p a r t y had been evacuated t o Hoodoo Creek by he l i cop te r . One v ic t im was l a t e r determined t o have d ied of a broken neck while t h e o the r s d ied of su f foca t ion .

AVALANCHE

The avalanche was a dry s l a b probably t r i g g e r e d by t h e v ic t ims, t h a t ran on t h e ground and was chanelled i n a gu l ly . The gu l ly was approxi- mately 10 m wide and had an average gradient of 45" over i t s 550 m v e r t i c a l f a l l . The maximum depth of t h e deposi ted snow was 1.5 m. The snowpack i n t h e a r e a was est imated t o be 40 cm deep and was comprised mainly of depth hoar.

COMMENT

The avalanche had a small volume, but ran on rock and sc ree . Owing t o i n j u r i e s sus ta ined during t h e f a l l t h e cl imbers probably were unable t o f i g h t t o s t a y on t h e surface .

The snowfall i n November and December of 1976 was unusually l i g h t and t h e shallow snow cover turned i n t o depth hoar i n almost a l l mountain a reas of southern B r i t i s h Columbia. Dr i f t ing snow formed a hard l aye r over the weak temperature-gradient snow i n g u l l i e s and t h e climbers '

probably f e l t t h e small amount of snow i n t h e g u l l y with such a hard su r face would be s a f e . I t could be t h a t they bel ieved t h e condi t ions "

were s i m i l a r t o those on a cold day i n t h e summer when t h e g u l l i e s a r e usua l ly f i l l e d with dense, s t a b l e snow.

Figure 12 Avalanche depos i t with t h e r e scue r s digging f o r t h e v ic t ims . (Photo cour tesy Royal Canadian Mounted Pol ice)

28 DECEMBER 1976

One snowmobile operator killed, one injured

LOCATION AND WEATHER

The accident site is on the shore of the St. Lawrence River, 3 miles east of Tadoussac, Comt6 Dubuc, Qu6bec. December 28th was a clear, calm day.

ACCIDENT I

A party on three snowmobiles triavelled through a snow covered sand dune area. While they were traversihg the bottom of a steep slope an avalanche released from above and stiruck them. One driver was completely buried, a second was injured and the third one escaped. Two of the snowmobiles were destroyed. The time of the accident was approximately 1400 h.

RESCUE

An intense search for the buried victim was initiated at 1600 h and continued until 2100 h when the victim's body was located underneath 4 m of snow.

AVALANCHE

The slab avalanche, probably triggered by the snowmobiles, occurred on a south facing slope, was 250 m long and 300 m wide, and deposited snow to a depth of from 3 to 4 m. Northwest wind had accumulated deep packed snow on a base of what was described as granular snow.

COMMENT

The granular, loose snow at the avalanche bed surface was probably the result of a temperature gradient. As other cases have already demonstrated the possibility of avalanches in eastern Canada must not be ruled out.

PARKER RIDGE, BANFF NATIONAL PARK, ALBERTA 15 FEBRUARY 1977

One s k i e r k i l l e d

WEATHER

Observations a t Parker Ridge study p l o t 2030 m ASL

Temperature New Snow Average O C Snow Depth Wind

Date Max Min cm cm km/h

11 February 4 -10.5 2 7 4 SW 27

12 February -0.5 -10.5 2 7 6 SW 32

13 February 1.5 -10 7 79 SW 35

14 February 3 -15 74 SW 18

15 February 1 .5 -11 7 3 SW 35

February 15th was a cool , cloudy day a t Parker Ridge.

ACCIDENT SUMMARY

On 15 February seven people who were s t ay ing a t t h e Hilda Creek Youth Hostel skied i n t h e Parker Ridge a rea . A t approximately 1600 h four of them came t o a s h o r t s t e e p s lope c l o s e t o t h e Hostel . The leader , watched by another member of t h e group, entered t h e slope from the s i d e j u s t below a small cornice and f e l l . The observer had turned h i s head toward the o t h e r s k i e r s but h i s a t t e n t i o n was a t t r a c t e d by a sound coming from t h e s lope i n f r o n t . When he turned around he discovered t h a t t h e s lope had avalanched and the group leader had disappeared.

RESCUE

The s k i e r s began a search of t h e deposi t ion while one of them went t o t h e Hostel f o r he lp . The d r i v e r of a passing c a r was n o t i f i e d and i n t u r n contacted the Jaspe r Park Wardens by phone from t h e Tangle Creek work camp a t 1635 h. A p a r t y of t h r e e wardens and a t r a i n e d avalanche dog were dispatched from Jasper a t 1655 h .

Meanwhile t h e s k i p a r t y members had begun digging where they thought t h e v ic t im was bur ied , which l a t e r proved t o be 10 m away from t h e a c t u a l loca t ion . A t 1745 h t h e park wardens' f i r s t search p a r t y a r r i v e d . By t h i s time t h e survivors had dug up a l a r g e a rea of the avalanche deposi t ion . A t 1750 h t h e dog located t h e v ic t im bur ied under about 60 cm of snow. He was dug out and cardiopulmonary r e s u s c i t a t i o n attempted but t h e v ic t im had d ied of su f foca t ion .

AVALANCHE

P reva i l ing southwesterly winds had loaded t h e t o p of t h e s lope and a t t h e same time scoured t h e bottom leaving a very uns table "hanging" s l a b . This was evident by t h e absence o f a "stauchwall". The avalanche was a hard s l a b with a depth varying between 2 and 70 cm, and moved only a s h o r t d i s t ance . The shear f a i l u r e occurred on a c r u s t , which was covered by su r face hoar , approximately 20 cm above the ground (Figure 13). The s lope had an ENE aspect and an i n c l i n e i n t h e s t a r t i n g zone of 35 t o 40°.

Another f a t a l avalanche occurred a t t h e same loca t ion 9 December 1967. (Stethem and Schaerer 1979)

COMMENT

The p a r t y was inexperienced i n s k i mountaineering and had n e i t h e r r e g i s t e r e d nor discussed avalanche condi t ions with t h e National Park Wardens.

The survivors made a se r ious mistake by digging immediately i n t h e avalanche snow where they thought t h e v ic t im was bur ied . When they d id not f i n d him t h e r e they continued digging nearby. By probing f irst with sk ipoles and s k i s they would have been much more successful i n loca t ing t h e buried person. I t was unfor tunate t h a t t h e o the r s were not watching when the s k i e r was caught i n t h e avalanche

REFERENCE

Stethem, C . J . and Schaerer, P.A. Avalanche Accidents i n Canada. I . A Se lec t ion of Case H i s t o r i e s , 1955 t o 1976. National Research Council of Canada, Division of Building Research, NRCC 17292, P. 39-40.

Figure 13 Fracture line profile, observed on 16 February 1977 by Parks Canada

VVI I I Y C > > m l - BROKEN SLAB - - - -

BURIED V I C T I M

Figure 14 Sketch of the accident site

- 45 -

DIANA LAKE, ROCKY MOUNTAINS, B.C. 16 MARCH 1977

One skier killed

WEATHER

Snowfall prevailed on the morning of 16 March at Diana Lake, depositing about 10 cm of new snow.

ACCIDENT

Ten skiers plus a guide waited in a cabin near the lake planning to helicopter to a ski run when the weather cleared. At 1230 h weather had improved and the guide decided to take the party out after lunch.

For the first run the guide chose a gully on Table Mountain Ridge, adjacent to the lake. The helicopter dropped the group on the ridge top, elevation approximately 2450 my and from there the skiers traversed towards the gully. The guide skied to a rock outcrop part way down the gully where he waited for the rest of the group. Then he continued his descent, stopped at another outcropping, about two-thirds of the way to the bottom, and after gathering his clients, directed them to continue in the gully to the helicopter pick-up while he would follow at the rear. When the first couple of skiers reached the trees in the meadow below the gully, an avalanche released from a slope above and adjacent to the gully. Although the guide and other party members shouted warnings, some skiers who were near the transition of the gully to a broader slope below, were caught. The time was approximately 1515 h.

RESCUE

One buried person was discovered immediately after the avalanche came to rest. A head count revealed that a second must be buried and a transceiver search was initiated. All members of the party were wearing, and had practiced the use of, avalanche rescue transceivers. About 20 minutes after the accident the second person was located by transceivers and probing. He was buried about 1.2 m below the snow surface at the base of a small tree and, as was concluded later, had died almost instantly from the impact of hitting the tree. A doctor and a police officer were later flown to the site, and the victim's body removed to Golden.

AVALANCHE

The avalanche started as a slab that fractured to a depth of approximately 30 cm in old snow layers. It ran over 200 m difference of elevation with a width of 45 m and deposited snow to a maximum depth of 2 m. The gully itself had a SSW aspect, but the avalanche started on a WNW slope at an elevation of 2400 m.

COMMENT

Only 1.5 m of snow had accumulated a t Diana Lake u n t i l 16 March whereas t h e normal accumulation would be 4 t o 6 m. Owing t o depth hoar and surface hoar formed i n December and January t h e snow cover was i n a c r i t i c a l condit ion throughout the Rocky Mountains i n March 1977. Previous t o t h e acc ident t h e guide o f t h e p a r t y had re leased numerous avalanches by s k i c u t t i n g i n order t o s t a b i l i z e t h e s k i runs, and t h e usual response of t h e snowpack was an abrupt s e t t l i n g and deep s l a b f r a c t u r e .

The f a t a l avalanche f rac tu red approximately 250 m from t h e nea res t point of the rou te t h a t t h e group followed. An a l p i n e s k i tour ing p a r t y had made about four runs on t h e same exposure on t h e previous day without not ing any avalanche a c t i v i t y , but probably t h e snowfall i n t h e morning and t h e sun i n t h e afternoon of 16 March decreased t h e s t a b i l i t y of t h e snow t o a c r i t i c a l l e v e l . Although t h e s k i i n g p a r t y found t h e snow s t a b l e i n t h e gu l ly , shocks crea ted by s k i i n g and t ransmit ted through t h e snowpack could have produ'ced t h e f a i l u r e on an adjacent s lope . I t was a l s o speculated t h a t t h e propwash of t h e h e l i c o p t e r f l y i n g across t h e avalanche s t a r t i n g zone a f t e r he dropped o f f t h e s k i e r s and when it landed a t t h e bottom could have d is turbed t h e a l ready d e l i c a t e balance of s t r e s s e s and s t r eng th i n t h e snowpack. In any case t h e snow was a l ready i n a very uns table condi t ion and t h e s k i e r s j u s t a s well a s o t h e r small d is turbances could have t r i g g e r e d t h e avalanche.

Steep g u l l i e s a r e bes t avoided whenever t h e r e i s even a remote chance of an avalanche, because they a r e c o l l e c t o r s f o r d r i f t i n g snow and avalanches t h a t s t a r t on adjacent s lopes . People caught i n the channelled avalanche snow a r e o f t e n bur ied deep.

BUGABOO, PURCELL MOUNTAINS, BRITISH COLUMBIA

Three s k i e r s k i l l e d

WEATHER

Observat ions a t Bueaboo Lodee. 1490 m ASL

17 MARCH 1977

Temperature P r e c i p i t a t i o n O c

Date Max Min mm

13 March 0 -11

14 March -3.5 -18.5

15 March - 3 -22

16 March 0.5 -10.5

17 March -0.5 -16.5

The sky was p a r t l y cloudy on 17 March and t h e temperature approximately - 6 ' ~ on t h e "Groovy Run" a t 1500 h .

Natural avalanches had been observed on south s lopes dur ing t h e week p r i o r t o 17 March and t h e s k i gu ides i n t h e a r e a were cau t ious .

ACCIDENT SUMMARY

Eleven persons and a guide were s k i i n g i n t h e a r e a surrounding t h e Bugaboo Lodge 17 March. S h o r t l y a f t e r lunch t h e group landed by h e l i c o p t e r a t t h e t op o f "Groovy Run" where ano the r group had preceded them. The guide t r a v e r s e d t h e s lope beyond t h e t r a c k s of t h e previous group and checked t h e snow by probing with t h e s k i po le . Then he sk ied down t h e s lope and s i g n a l l e d t h e group t o fo l low.

The ma jo r i t y of t h e s k i e r s reached t h e bottom s a f e l y , bu t a s t h e l a s t few moved onto t h e s lope t o descend, an avalanche r e l e a s e d . Three out o f t h e fou r s k i e r s s t i l l a t t h e t o p were caught and c a r r i e d downhil l . When t h e avalanche came t o r e s t t h e t h r e e were p a r t i a l l y bur ied but o therwise seemed a l l r i g h t . The r e s t o f t h e group was c l e a r of t h e avalanche and s t a r t e d t o go u p h i l l t o he lp . A few seconds l a t e r

a second, l a r g e r avalanche came down t h e slope and enveloped t h e p a r t l y buried vict ims. A warning shout from t h e guide allowed t h e o the r s t o move c l e a r of the second avalanche. When t h e snow ha4 s e t t l e d t h e t h r e e s k i e r s who had been caught before were now completely bur ied . The time was approximately 1500 h .

RESCUE

The guide and o the r p a r t y members immediately wept t o t h e area where the t h r e e s k i e r s had been bur ied . The second avalanche had deposi ted a much l a r g e r volume o f snow on top of t h e f i r s t . A l l t he s k i e r s c a r r i e d rescue t r a n s c e i v e r s and t h e searchers picked up s i g n a l s almost immediately when they switched t h e i r ins t ruqen t s t o t h e rece ive mode. Af ter p inpoint ing t h e loca t ions they began t o d i g . Other groups had been summoned by r a d i o and add i t iona l he lp began t o a r r i v e by h e l i c o p t e r a f t e r about t e n minutes.

The v ic t ims were buried between 3 and 5 m deep and digging became very d i f f i c u l t . The f i r s t v ic t im was not found u n t i l 45 minutes had elapsed, t h e l a s t one a f t e r 14 hours; a l l t h r e e were dead when found.

AVALANCHE

The avalanche s t a r t e d a t an a l t i t u d e of 2600 m and ran 150 m v e r t i c a l l y over a width of 70 m. The i n i t i a l f r a c t u r e occurred near t h e s k i e r s then propagated around a rock spur and across t h e top of t h e adjacent s lope. The avalanche f rac tu red i n a l aye r of su r face hoar 1 .1 m below t h e su r face , then t o r e i n t o depth hoar and t o t h e ground i n some p a r t s of t h e t r a c k . The avalanche s lope had an average gradient of 3 9 O and a NW aspect .

The a rea had been skied e a r l i e r i n t h e week, but new snow had almost completely covered t h e o ld t r a c k s .

COMMENT

The deep b u r i a l g r e a t l y reduced t h e chance f o r survival of t h e s k i e r s who undoubtedly died soon of suffocat ion i n t h e densely packed, deep snow. In s p i t e of the r ap id discovery of t h e b u r i a l spo t s by rescue t r ansce ive r s and t h e l a rge number of rescuers and shovels on s i t e , it took too much time t o d ig i n t o t h e deep avalanche snow. I t i s i n t e r e s t i n g t o note t h a t t h e v ic t ims were so deeply buried t h a t t h e searchers could not pick up a s igna l with t h e lowest volume s e t t i n g of t h e t r ansce ive r .

The case demonstrates again t h e hazard from a second avalanche from an adjacent s lope a f t e r t h e f i r s t one has occurred.

Figure 16 Photograph of the avalanche. The ski ing p a r t y entered the slope from the l e f t ; t h e f i r s t avalanche broke a t t h e l e f t s ide , and t h e second, l a r g e r one came from t h e r i g h t . (Photo courtesy Canadian Mountain Holidays) @ Location of the buried persons

BOW PEAK, BANFF NATIONAL PARK, ALBERTA 19 MARCH 1977

One cl imber k i l l e d

WEATHER

During t h e seven-day pe r iod p r i o r t o 19 March only 2 cm of new snow was recorded a t t h e observa t ion s t a t i o n a t Bow Summit 2020 m above s e a l e v e l . The tempera tures f o r t h e pe r iod remained well below O°C. On 19 March t h e sky was ove rcas t , t h e wind was l i g h t from t h e sou theas t , and t h e temperature reached a maximum of -5°C.

ACCIDENT SUMMARY

A t approximately 1415 h on 19 March two c l imbers l e f t t h e i r camp on Crowfoot Pass f o r a climb of Bow Peak v i a t h e n o r t h r i d g e . They had d iscussed t h e r o u t e wi th Parks1 s t a f f on t h e previous day and had been warned t o s t a y away from avalanche g u l l i e s . A t 1730 h t h e p a i r had reached t h e summit.

The c west f a c e c l imber wa

l imbers decided t h a t t h e y would g l i s s a d e down a g u l l y on t h e r a t h e r than t o descend by t h e n o r t h r i d g e . When t h e f i r s t s approximately 200 m below t h e summit, t h e second one began

h i s descent . A s soon a s he s t a r t e d g l i s s a d i n g an avalanche r e l e a s e d about 5 m above him. H e was a b l e t o a r r e s t h imsel f wi th h i s i c e axe and shouted "avalanche!" t o h i s companion below. The f i r s t c l imber , however, was overrun by t h e avalanche and d isappeared from s i g h t .

RESCUE

Fearing f u r t h e r avalanches t h e second c l imber s tayed pu t f o r a few minutes, then kicked s t e p s down t o t h e avalanche depos i t i on and began t o search f o r h i s companion. F i r s t he d iscovered a h a t and then s p o t t e d a hand p ro t rud ing from t h e snow about 3 m away. About 40 minutes had e lapsed s i n c e t h e avalanche occurred . The su rv ivo r immediately dug out h i s companionls upper body and found him i n j u r e d bu t b rea th ing . The v i c t im was unable t o move a s h i s lower body was s t i l l bur ied . Af t e r a h a l f an hour o f d igging t h e second c l imber became exhausted but s t i l l had no t f r e e d t h e v i c t i m ' s l egs .

The unin jured c l imber then decided t o go f o r h e l p because he thought it would t a k e only h a l f an hour t o reach t h e Banff-Jasper Highway. He l e f t h i s down j acke t with t h e v i c t i m and made h i s way back t o camp. Af t e r changing i n t o d ry c l o t h i n g he headed down t h e t r a i l , bu t f a i l e d t o t a k e a h a t , g loves , j acke t o r snowshoes. The t ime was approximately 1900 h and t h e highway was about 8 km away.

Shor t ly a f t e r leaving the camp t h e climber began t o break through t h e c r u s t and f lounder i n t h e snow. In darkness he crossed t h e Bow River, f e l l through t h e snow and i c e , and on t h e o the r s i d e began t o follow a snowmobile t r a c k . Soon he became d i so r i en ted and r e a l i z e d t h a t he could not go on. He made a bed of t r e e boughs and l a i d down f o r t h e n igh t .

A t dawn he walked t o Bow Lake and a f t e r about 15 minutes reached t h e highway where he f lagged down a passing maintenance t ruck . The d r i v e r immediately contacted t h e Park wardens by radio . Two wardens l e f t Lake Louise by h e l i c o p t e r a t 0750 h and landed a t t h e accident s i t e a t 0820. The v ic t im was found dead and was flown t o a wait ing ambulance on t h e Banff-Jasper Highway. Exposure was l a t e r determined a s t h e cause of death.

AVALANCHE

The s l a b avalanche, t r igge red by t h e g l i s sad ing cl imbers, had a f r a c t u r e about 25 m wide and 1.5 t o 2 m deep. The s t a r t i n g zone was a t an a l t i t u d e of 2800 m and t h e avalanche path was approximately 300 m long and 80 m wide with an average gradient o f approximately 357. The avalanche snow was deposi ted t o a maximum depth of 4.5 m.

COMMENT

The climbers were well equipped but had l imi ted winter mountaineer- ing experience. They had been warned about t h e avalanche hazard by t h e Park wardens. A s i n o the r acc idents , choosing a rou te through a snowfil led gu l ly i n the winter proved t o be a f a t a l e r r o r . Panic perhaps clouded t h e judgement of t h e survivor . Had he r e s t e d a moment and thought t h e s i t u a t i o n out he might have decided t o f r e e t h e buried man from t h e snow and s e t up an emergency s h e l t e r , thus saving t h e l i f e of h i s companion.

Figure 17 Westface of Bow Peak with the descent route of the climbers and the avalanche. (Photo Courtesy Jim Davies on 20 March 1977)

Figure 18 Snow profile at Bow Summit observation plot 2020 m ASL on 21 March 1977. (Observed by Parks Canada)

APEX MOUNTAIN, PENTICTON, B.C.

One s k i e r k i l l e d , one s k i e r in ju red

21 MARCH 1977

WEATHER

Observations a t t h e base of Apex Ski Area a t 0800 h

Temperature New Snow Date O C cm

18 March -6 2

19 March - 8 8

20 March - 2 2

2 1 March - 1 15

The snowfall ended a t 0600 h 21 March, and a t 1200 h t h e temperature was est imated a t +3OC.

ACCIDENT SUMMARY

Five s k i e r s , a f t e r s k i i n g f o r a few hours i n t h e new powder snow a t Apex Mountain, l e f t t h e pomalif t a t about 1300 h intending t o s k i the Tooth Chute, one of seve ra l chutes about 1 km away. No o the r s k i e r s had yet entered t h e chutes on t h a t day.

When they reached t h e chute t h r e e of t h e s k i e r s prepared t o e n t e r it from the s i d e about 10 m from t h e top. One o f them began t h e descent , f e l l , and l o s t h i s s k i , but was not observed by t h e o t h e r s because he was below t h e apex of t h e h i l l . A second s k i e r sk ied p a r t way down, saw h i s f a l l e n companion and pul led o f f t o t h e s i d e t o wait . The t h i r d s k i e r was about t o go when one of t h e two wait ing above jumped over a small cornice and began t o t u r n . A s he made h i s f i r s t t u r n an avalanche s t a r t e d and swept him down. The s k i e r s a t t h e s i d e of t h e s lope escaped, but t h e one who had l o s t h i s s k i was enveloped by t h e avalanche.

RESCUE

The s k i e r s unaf fec ted by t h e avalanche descended t o t h e depos i t ion a r e a and one l e f t immediately t o summon he lp from t h e s k i a r e a . The s k i e r who had been wai t ing bes ide h i s f a l l e n companion ind ica t ed t h e l a s t - s een po in t and t h e search began below t h a t p o i n t . About t e n minutes l a t e r t h e su rv ivo r s heard one v i c t im ( the fou r th s k i e r ) c a l l i n g from t h e dense f o r e s t . They t o l d him t o wait and continued looking f o r t h e s t i l l missing s k i e r . About 20 m below t h e l a s t - s e e n po in t they found a s k i po le and another 15 m below a h a t . About 6 m f u r t h e r down t h e s lope dense t r e e growth began where most of t h e snow seemed t o have stopped. Helpers from t h e s k i a r e a began t o a r r i v e and i n i t i a t e d a h a s t y search with probes below t h e l a s t - s e e n po in t concent ra t ing it towards t h e dense t r e e s while o t h e r s cared f o r t h e in ju red v i c t im . Approximately 30 minutes a f t e r t h e acc ident t h e buried v i c t i m ' s hand was discovered s t i c k i n g out of t h e snow, about 20 m from t h e in ju red s k i e r . Digging down t h e r e scue r s found t h e head 1 m below t h e su r f ace . No s i g n s of l i f e were evident bu t r e s u s c i t a t i o n was attempted t o no a v a i l . Both s k i e r s who were caught by t h e avalanche had been thrown about 30 m i n t o t h e dense f o r e s t .

AVALANCHE

The avalanche, t r i g g e r e d by t h e s k i e r s , s t a r t e d a s a new snow s l a b 40 t o 60 cm deep on a hard c r u s t , then i n t h e lower p a r t of t h e pa th t o r e t o t h e ground i n a base of depth hoar . The avalanche s t a r t e d a t an a l t i t u d e of 2100 m and r an 150 m v e r t i c a l l y . The crown had a width of 27 m and t h e t r a c k an average width of 14 m . The s lope has a n o r t h e a s t e r l y aspec t ( i n t h e l e e of t h e p r e v a i l i n g winds) and an average

. grad ien t of 38". The snow was depos i ted t o a maximum depth of 1 .5 m and a volume of approximately 600 m3. The snowpack i n t h e s t a r t i n g zone cons i s t ed of 60 cm of depth hoar ove r l a in by a s t rong c r u s t o v e r l a i n by 50 cm o f s o f t new snow. No o t h e r avalanche a c t i v i t y was noted i n t h e a r e a a t t h a t t ime.

COMMENT

The chute where t h e acc ident occurred i s ou t s ide t h e s k i a r e a , but i s a c c e s s i b l e r a t h e r e a s i l y from t h e top of t h e s k i l i f t , and was not p a t r o l l e d . Due t o t h e p o p u l a r i t y of powder s k i i n g and advances i n s k i equipment such s lopes prove t o be a t t r a c t i v e , which means t h a t s k i a r e a ope ra to r s must be aware of them and t h e i r avalanche p o t e n t i a l . Observation, s e l e c t i v e c l o s u r e s , and c o n t r o l a r e t h e b e s t methods of p r o t e c t i o n . Experience i n o t h e r a r e a s has shown t h a t permanent c lo su res a r e d i f f i c u l t t o enforce and a r e o f t e n v i o l a t e d un le s s t h e boundary i s supported by a c l e a r l y def ined geographic f e a t u r e such a s a r i dge l i n e o r c reeks .

QUARTZ RIDGE, BANFF NATIONAL PARK, ALBERTA

One s k i e r k i l l e d , four s k i e r s in jured

27 MARCH 1977

WEATHER

Observations a t Sunshine snow study p l o t 2145 m ASL

The accident s i t e a t Quartz r idge i s about 5 km southeast of Sunshine Vi l lage

Temperature New P r e c i p i t a t i o n Snow Wind O C Snow Depth

Date Time Max Min cm mm cm km/h

23 March 0800 -2 - 7 1 1 122 S 13 1500 +1 - 6 3 1 125 S 10

24 March 0800 -1 -14 6 6 128 S 13 1500 -2 - 8 1 0.5 129 S 5

25 March 0800 -2 -17 T - - 125 S 19 1500 -4 - 10 T - - 124 S 23

26 March 0800 -4 -13 8 4 132 S 23 1500 -6 - 9 3 2 132 S 2 3

27 March 0800 -5 -15 18 11 144 S 13 1500 -6 - 9 8 4 148 S 15

Moderate sou the r ly winds were sus ta ined a l l day 26 March and u n t i l 0100 h on t h e 27th. During t h e morning of 27 March whiteout condi t ions and heavy snowfall , with i n t e n s i t y g r e a t e r than 1 cm per hour, prevai led a t Sunshine Vil lage. An unusually shallow and unconsolidated snowpack containing depth hoar and su r face hoar toge the r with t h e recent snowfalls had produced uns table condi t ions i n t h e Rocky Mountains. The Wardens of the National Park had posted t h e avalanche hazard a s being extreme and t r a v e l i n avalanche a reas was not recommended.

ACCIDENT SUMMARY

A guide with 20 gues ts r e g i s t e r e d a t Sunshine Vi l lage a t 0930 h on 27 March intending t o hike on s k i s t o C i t ade l Pass. A t t h e park boundary they were t o be picked up by h e l i c o p t e r and flown t o Assiniboine Lodge. An add i t iona l 3 s k i e r s tagged along with t h e p a r t y .

The group l e f t t h e s k i a r e a a t about 1000 h and proceeded SSE along t h e a l p i n e rou te f o r one hour. A t about 1100 h t h e weather and v i s i b i l i t y were extremely bad so t h e guide decided t o t ake t h e p a r t y dolsn i n t o t h e t r e e d bas in of Howard Douglas creek. A shor t time l a t e r , while cross ing a shor t s t eep s lope , one member of t h e p a r t y was caught i n a small avalanche and c a r r i e d down f o r approximately 30 m on t h e surface . He was unhurt and t h e group continued through t h e t r e e s , s topping f o r lunch along t h e way.

A t 1400 h t h e p a r t y reached an open a rea . Poor v i s i b i l i t y l imi ted t h e view of t h e s lopes above. The guide skied approximately 15 m across the s lope then suddenly not iced snow f r a c t u r i n g above and behind him. With a warning shout t o t h e o t h e r s he turned h i s s k i s downhill and escaped t h e avalanche. The main body o f t h e avalanche, however, came from well above t h e group, ran over open s lopes and through t h e t r e e s where t h e major i ty of t h e p a r t y were located. The guide and t h e f i r s t two p a r t y members gained a s a f e pos i t ion below a rock outcrop, but t h e avalanche h i t seven s k i e r s burying f i v e of them.

RESCUE

Af te r t h e avalanche had stopped t h e guide hur r i ed back t o h i s c l i e n t s . He noted a s k i t i p i n t h e snow, dug down, and uncovered a male survivor . Af te r d ispatching two persons t o Sunshine f o r he lp t h e guide i n s t r u c t e d o the r s t o probe with s k i poles i n l i k e l y b u r i a l a r e a s . Three women were found almost immediately, buried agains t t r e e s . They were conscious but s u f f e r i n g from shock and minor i n j u r i e s . The guide located a f i f t h buried person with a probe 30 t o 45 minutes a f t e r t h e acc ident . She was found by a t r e e under approximately 2 m of snow, exhibi ted no s igns of l i f e , and d id not respond t o a r t i f i c i a l r e s p i r a t i o n . Lower down on t h e s lope a f i r e was s t a r t e d and t h e in ju red survivors cared f o r .

A t 1705 h t h e two messengers a r r i v e d a t Sunshine Vil lage and reported t h e acc ident . A rescue p a r t y was dispatched a t 1745 h and t r a v e l l i n g by oversnow veh ic le and s k i i s a r r ived a t t h e accident s i t e a t 1845 h. A t 1900 h 13 of t h e survivors and a guide l e f t v i a a s a f e rou te f o r a snowcat pickup and r i d e t o Sunshine Vi l lage . A t 2300 h some of t h e r e scuers and a b l e survivors l e f t t h e s i t e f o r t h e snowcat pickup while t h r e e rescuers , the four in ju red s k i e r s and t h e deceased remained a t t h e s i t e overnight . A t 0645 t h e next morning a h e l i c o p t e r c a r r i e d t h e remaining persons t o Banff.

AVALANCHE

The avalanche occurred a t 2100 m ASL on a 's tepped' e a s t fac ing slope, f r ac tu red t o an average depth of 85 cm with a width of 300 m and ran approximately 320 m . The bed surface was l i k e l y surface hoar (Figure 19). There were t h r e e s t a r t i n g zones with s lope angles varying from 36 t o 3g0, and t h e average i n c l i n e of t r a c k was 29'. The maximum depth of t h e deposi ted snow was 3.3 m.

The rescuers noted numerous new natural avalanches in the valley when they flew out the morning after the accident.

COMMENT

In a public inquiry held 5 August 1977 the jury determined the death as being accidental and made the following recommendations to prevent similar accidents.

- Two guides shall accompany a party of this size.

- Electronic homing devices shall be carried for parties of commercial cross country tours.

- All guides shall check the available avalanche hazard informat ion.

T E M P E R A T U R E , "C

Figure 19 Snow profile at Sunshine Study plot on 28 March 1977 (Parks Canada)

LAKE LOUISE, ALBERTA

One s k i e r k i l l e d

WEATHER AND AVALANCHES

Observat ions a t Temwle s tudy wlot 1975 m ASL

30 MARCH 1977

Temperature New P r e c i p i t a t i o n Snow Wind " C Snow Depth

Date Time Max Min cm mm cm km/h

26 March 0800 -3 -11 T 92 NW11 1530 -3 -9 1 0.2 9 2 W 2 2

27 March 0800 - 3 -9 2 0.5 93 SW 11 1530 -6 -9 7 1 .5 100 W 19

28 March 0800 -8 -18 2 1.5 102 Calm 1530 -3 -8 - - 100 N 4

29 March 0800 -2 -18 - - 100 Calm 1550 +2 -16 - - 9 7 N 9

30 March 0800 + 2 -15 - - 97 NIV 25

The temperature a t t h e t ime o f t h e acc ident was 2 O C and t h e sky was o v e r c a s t .

Seven and t h r e e avalanches of s i g n i f i c a n t s i z e were i n i t i a t e d with exp los ives i n t h e Lake Louise s k i a r e a 28 and 29 March, r e s p e c t i v e l y . One of t h e 28 March avalanches occurred i n t h e Flush Bowl and was small t o medium s i z e d i n su r f ace snow. No f u l l depth avalanches were observed dur ing t h e w in t e r i n t h e Flush Bowl.

ACCIDENT SUMMARY

A t approximately 1215 h on 30 March two s k i e r s t r ave r sed from t h e t o p of t h e Larch C h a i r l i f t t o t h e Flush Bowl. They had made a run t h e r e e a r l i e r t h a t morning wi th about t h i r t y o t h e r s k i e r s , a l l o f whom had passed a "Danger Avalanche Area" s i g n and a "Ski Area Boundary" s ign , before e n t e r i n g t h e bowl.

Af te r reaching t h e bowl one o f t h e two men sk ied down, stopped a t t h e bottom, and watched t h e descent o f h i s companion. With a sudden y e l l t h e second s k i e r came r ac ing down t h e s lope i n f r o n t of an avalanche, which soon overran and engulfed him. Luckily t h e f i r s t s k i e r was a b l e t o ge t ou t of t h e way. The time was approximately 1230 h .

RESCUE

The v i c t i m ' s companion watched t h e avalanche, saw t h e s k i e r d i sappear , then sk ied t o t h e n e a r e s t t r a i l where he f lagged down another s k i e r who went t o r e p o r t t h e acc ident t o t h e Lake Louise Ski P a t r o l . The companion r e tu rned t o t h e avalanche s i t e where he discovered t h e v i c t i m ' s hand on t h e su r f ace . He began digging and had j u s t exposed t h e head under 35 cm o f avalanche snow when t h e s k i p a t r o l ' s f i r s t rescue p a r t y a r r i v e d a t 1304 h. The v i c t im was bur ied face up, was unconscious and not b rea th ing .

The r e scue r s administered a r t i f i c i a l r e s p i r a t i o n , but no response was noted. A doctor a r r i v i n g on t h e s i t e pronounced t h e s k i e r dead; it was l a t e r determined t h a t su f foca t ion was t h e cause of dea th . The v i c t im was evacuated by toboggan t o a wai t ing ambulance.

AVALANCHE

The f r a c t u r e l i n e p r o f i l e shows two weak, bur ied su r f ace hoar l a y e r s and depth hoar . The s l a b avalanche f r a c t u r e d on t h e su r f ace hoar 112 cm from ground (86 cm from t h e t o p ) , then removed t h e snow cover t o i t s f u l l depth f u r t h e r down t h e s lope . A s i m i l a r snow s t r u c t u r e was observed i n o t h e r p a r t s of t h e Rocky Mountains i n March 1977 and was t h e cause of o t h e r acc iden t s and numerous n a t u r a l avalanches.

The s k i t r a v e r s e i s a t an a l t i t u d e of 2280 m and t h e f r a c t u r e occurred approximately 60 m above t h a t . The avalanche ran over a length of approximately 240 m with a maximum width o f 80 m on a s lope with a northwest aspec t and an average g rad ien t o f 35'. The snow was depos i ted t o a maximum depth of 2 m and t h e v i c t im was bur ied approximately 13 m from t h e t o e o f t h e depos i t i on .

COMMENT

The avalanche pa th had been t r e a t e d with a r t i l l e r y f i r e two days before t h e acc ident and an avalanche was r e l e a s e d , but obviously not a l l of t h e uns t ab le srlow was removed. The a r e a was not c losed on t h e day of t h e acc ident bu t was posted with warning s i g n s . Experience t h e r e and i n o t h e r s k i a r e a s has shown t h a t prolonged c losu res of a t t r a c t i v e and r e a d i l y a c c e s s i b l e s k i s lopes a r e d i f f i c u l t t o enforce . In such cases it i s b e s t t o c o n t r o l avalanches by exp los ives , i f necessary i n repea ted a t tempts with d i f f e r e n t t a r g e t s , l a r g e r charges, and whenever t h e weather might have caused t h e snow s t a b i l i t y t o decrease .

I f t h e v i c t i m ' s companion had made a h a s t y search of t h e avalanche depos i t before going t o r e p o r t t h e acc ident he would have not iced t h e hand of t h e v i c t i m sooner and might have saved h i s l i f e .

Figure 22 Fracture line profile, observed on 1 April 1977 by Parks Canada

m I- Z W

r 5 3 u

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X "+ -0.5 -

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E r n =

L r z > 3

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E

E c t

N - v,

Z - a CL a

Y a a

a ", a

m v,

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I = z a = - -

T E M P E R A T U R E , O C

-12 - 1 0 - 8 - 6 - 4 - 2 I l l l l l l l l l l l l . l ~ l ~ l ~ ' 1 ~ 1 ~ 1 '

6 0 5 0 4 0 3 0 2 0 1 0 R A M R E S I S T A N C E , k g - X.,

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I-

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MT. ATHABASCA, JASPER NATIONAL PARK, ALBERTA 7 SEPTEMBER 1977

Two climbers injured

WEATHER

Observations at Parker Ridge study plot 2030 m ASL

Temperature Precipitation Oc

Date Max Min. mm

5 September 10.5 0 20 (since 3 September)

6 September 11.5 -0.5 1.5

7 September 12 - 1 0.5

8 September 9.5 - 2 2

In late August and early September snow had started to accumulate at higher elevations on the Columbia Icefield. Overcast skies and intermittent snowfall prevailed on 7 September.

ACCIDENT SUMMARY

On 7 September two climbers ascended Mt. Athabasca (3465 m) via the standard route. Descending from the summit they walked roped up and when they traversed a slope parallel to the bergschrund at approximately the 2980 m level the leader was caught by an avalanche that came from Mt. Silverhorn. The second man was able to hold the rope until the leader was swept over the icefall, then he too was pulled off. The two climbers fell 15 to 20 m to the snow below and both were severely injured.

RESCUE

Other climbers in the campground noticed the absence of the victims and reported it to the attendant on the morning of 8 September. He in turn alerted a park warden at 0700 h. A rescue party of three left on foot immediately, reached the site at 0830 h, and immediately

found the injured climbers who were suffering from multiple injuries and hypothermia. A helicopter dispatched from Banff arrived at the accident site at 0930 h and was able to land 25 m from the injured persons. The two climbers, one in serious condition, were then flown to the hospital.

AVALANCHE

The avalanche, starting as a loose snow avalanche, was not particularly large but was powerful enough to carry the leader down the slope over the icefall and then to pull down the second belay man.

COMMENT

The two men were experienced climbers. During the night the less injured climber was able to keep the severly injured lead climber warm using massage and his own body heat. Had it not been for this action the first climber would probably not have survived the night.

PRESIDENT'S COL, YOHO NATIONAL PARK, BRITISH COLUMBIA 9 OCTOBER 1977

One cl imbcr ki 1 led

WEATHER

During the late afternoon of 8 October a snowstorm deposited about 4 cm of new snow on top of the 2 cm already on the ground in the Little Yoho Valley. At higher elevations around President's Col an estimated 10 to 15 cm of snow fell. In the early morning of 9 October the temperature was below O°C and the sky was cloudy; there was a light snowfall and moderate southwest wind.

ACCIDENT

At 0700 hours on 9 October 13 climbers left the Alpine Club of Canada hut in the Little Yoho Valley intending to climb Mts. President and Vice President via President's Glacier and President's Col. At approximately 1000 h the first rope party of 3 climbers came to a large bergschrund about 175 m below President's Col. Shortly after the lead climber had crossed the bergschrund an avalanche released from above and swept him into the bergschrund where he was buried by the avalanching snow The second and third climbers were partly buried on the downhill side of the bergschrund.

RESCUE

The persons in the second rope party, who were close behind the lead climbers, came to the aid of the two partly buried persons, then following the rope began to dig for the climber buried in the bergschrund. Progress was extremely slow due to the lack of shovels, the loose snow, and the steep confining walls of the crevasse.

One climber left for help at 1230 h, and after hiking 11 miles and travelling 10 by vehicle he reported the accident to the park wardens at 1445 h. The first rescue party dispatched by helicopter at 1545 h arrived at the scene at 1600 h and a follow-up party at 1700 h. Buckets and shovels were used to remove the snow from the bergschrund and the victim was located 15 m down from the edge of the bergschrund at 1750 hours. He had died of suffocation.

AVALANCHE

The avalanche released at an altitude of 2430 m. It was a dry slab avalanche of new snow and fractured with a depth of 20 cm on old firn across a width of 10 m. It ran a length of 90 m on a 35" slope and deposited snow to a maximum depth of 10 m in the bergschrund. the avalanche was probably triggered by the lead climber.

The s lope had a no r theas t exposure and was i n t h e l e e of t h e southwest wind t h a t p reva i l ed during snowstorms.

COMMENT

This case demonstrates t h a t a r e l a t i v e l y small amount of new snow can produce dangerous avalanches on s t e e p s lopes of f i r n and i c e , hence mountain cl imbers must be aware of avalanche hazards i n t h e summer a s wel l a s i n t h e win ter . The hazard i s magnified by crevasses t h a t ca t ch t h e avalanches and t h e i r v i c t ims .

The deep b u r i a l and slow digging because of t h e loose snow and confined space account f o r t h e long recovery t ime. Even i f t h e climbing p a r t y had c a r r i e d shovels t h e time would have been long and t h e s u r v i v a l chance of t h e bur ied person low. Due t o t h e confined space i n t h e bergschrund t h e park wardens found buckets were t h e most u se fu l implement i n removing t h e avalanche snow quickly and e f f i c i e n t l y .

WHISTLER MOUNTAIN, B.C.

Two ski patrollers buried

WEATHER AND SNOW

Weather observations were made at the

8 MARCH 1978

Whistler Alpine study plot 1870 m ASL

Between 16 February and 6 March only 6 cm of new snow was recorded. On 19 February light rain formed a thin crust on the snow and between 25 February and 4 March low overnight temperatures and clear skies produced a substantial temperature gradient in the top 25 cm of the alpine snowpack and surface hoar on northwest, north and northeast slopes. During this period skiers noticed extensive audible snow settlement in untracked alpine back country.

A storm cycle began 6 March. In view of the unstable layers in the upper snowpack observers expected extensive avalanche activity. The snowfall continued 7 March and tapered off in the early morning hours of 8 March (Figure 23). Shovel tests and tilt board observations at 0800 h 8 March indicated a primary weakness approximately 60 cm below the snow surface in a layer of mixed surface hoar and immature temperature gradient crystals. No significant increase in the shear strength of this layer was measured between 0800 March 7th and 0800 March 8th, but the snow load increased considerably.

On 7 March small to medium sized avalanches were initiated with explosives on the northern and northeastern slopes and a small natural one occurred on a northeastern exposure. On 8 March medium to large sized avalanches were again released with explosives on the northwestern, northern and northeastern slopes.

ACCIDENT SUMMARY

Visibility was unlimited at 0845 h 8 March and the avalanche control supervisor decided to carry out a full avalanche control. Not only would the slopes within the ski area be controlled but also those of the surrounding terrain. The Gun 2 crew began to shoot at the slopes of Upper Harmony Bowl and Glacier Bowl at approximately 0930 h. By that time the visibility had deteriorated to variable and at times limited. Avalanches were released on northwestern and northeastern slopes though at times these were only heard rather than seen. Only one shot was fired into the Whistler Peak North Face area but the result could not be observed because the face was obscured by cloud.

At approximately 1115 h six men departed from the top of the T-bar for the stabilization of the Surprise Shale and Whistler Bowl areas. At 1125 h the Surprise Shale team initiated a large avalanche on Surprise Path with hand charges. As the team climbed back on the lateral moraine below the North Face the four other patrollers were on the high traverse below the North Face, and when the last one of them had reached the middle of the slope an avalanche started above. The patrollers on the moraine below yelled a warning but two members of the group on the traverse were caught in the avalanche and were buried when it stopped. The time was 1130 h.

RESCUE

The patrollers not touched by the avalanche immediately called by radio for assistance. Because his arm was visible at the edge of the avalanche one of the buried men was found immediately and dug out. The two patrollers who had watched the accident from the moraine started a search with transceivers in the area where the second victim was last seen. His location was soon indicated by the transceivers then pinpointed by probing with a ski. Digging with their hands the patrollers found the victim under 1.2 m of snow. He was blue in the face and not breathing, but started breathing and gained consciousness quickly once his mouth was cleared of snow. At 1137 h a three-man party arrived with shovels and probes. The victim was freed completely with a large shovel and at approximately 1155 h a doctor, who was a member of the ski patrol, arrived and examined the victims. They were dispatched by helicopter to the Alpine Office where both of them recovered completely within a few hours.

I AVALANCHE

The slab avalanche started at approximately 2050 m ASL on a slope with a northerly aspect and 44" incline. The slab itself covered an area of approximately 4000 m2 and varied from 30 to 90 cm in depth. The avalanche ran 60 m vertically. The deposited snow had a maximum depth of 3 m but was spread over an area of about 5000 m2.

I COMMENT

Control work at the Whistler High Traverse is usually attempted only during periods of good visibility. The single gun shot, too high on the slope, did not release an avalanche, therefore a second shot should have been placed lower on the slope, but poor visibility prevented the gun crew from assessing the result and so firing again. Undoubtedly the group traversing the "transition" area of the North Face triggered the avalanche, but the skiers were well spaced across the slope, therefore not all of them were caught.

Fortunately the victims were found quickly visually and with transceivers and ski probing and they could be dug out fast enough by hand. Nevertheless, avalanche control teams should not carry transceivers only, they should also have probes and shovels for quick recovery of buried persons.

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Figure 23 Storm profile

Figure 24 Fracture line profile observed on 9 March 1978

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Figure 25 View of the avalanche site (Photo C. Stethem) @ Location of buried patroller, found after 7 minutes x Location of patroller who was found immediately