backcountry access − 0 avalanche avoidance and companion rescue

Backcountry Access − 1

Avalanche Avoidance and Companion Rescue


Outline• Who’s at risk

• Types of avalanches

• What causes avalanches

• Avalanche avoidance

• Companion/beacon rescue

• Educational resources

• Q and A


who’s at risk

Snowmobilers lead North America in fatality statistics


who’s at risk

Snowmobilers don’t understandthe causes of avalanches


types of avalanches

Slab Avalanchescause almost all avalanche fatalities


types of avalanches

Point Release Avalanchesmore easily predicted, usually less dangerous


• Weather

• Terrain

• Snowpack

• Human Factors

what causes avalanchesUnderstanding what causesavalanches will help you avoid them


New snow adds weight (stress) to the snowpack.

New snow takes time to bond to layer underneath.

what causes avalanches − weather

Most avalanches occur duringand after storms


CorniceCornice

Wind loading directionWind loading direction

LoadingLoading

Notice anything else?Notice anything else?

CrownCrown


Wind transports snow (weight)


• Rapidly warming temperatures can weaken the snowpack

• You can have stability at one elevation but as you climb or descend the snow profile can change

• Similarly, a slope at one aspect can be safe but at a slightly different aspect can be very unstable

Temperature, elevation & aspectall will affect snowpack stability



The majority of avalanches occuron slopes between 30°- 45°

what causes avalanches − terrain


• Most slabs release on thebulge of convex slopes

• Slabs can be triggeredfrom above and belowthe slope

ConcavityConcavity

ConvexityConvexity

Slope shape is also a factor



Dense trees can act as “anchors”and points of safety



• Learn to evaluate the snowpack

• There’s no substitute for on-snow avalanche instruction

• Take a Level I avalanche course

• Practice

what causes avalanches − snowpack

Weak snowpackusually a strong layer over a weak layer


Some slab avalanches are huge



1. Skier1. Skier

2. Slope convexity2. Slope convexity

3. Roughly 30 degrees3. Roughly 30 degrees

4. Debris slid into concavity4. Debris slid into concavity

5. Yes!5. Yes!

1. What triggered this slide?1. What triggered this slide?

2. Where did the slope 2. Where did the slope fail?fail?3.3. What’s the slope angle? What’s the slope angle?

4. Where did the debris flow?4. Where did the debris flow?

5.5. Could this slide have killed Could this slide have killed you?you?


Killer avalanchesmost are small and human triggered


• Call local avalanche forecast center

• Know the snowpack history

• Talk to others who have been out

Know before you go!



Human factors

what causes avalanches − human factors

Attitude:People sometimes ignoredanger signs due to pride,ego and ambition.

Time:Weekend warrior syndrome.

Blue Sky:Sunny weather sometimesdraws people too soon aftera storm.

Herding Instinct:People tend to think less in large groups.


1. Expose only one person at a time 1. Expose only one person at a time

2. Stay out of avalanche run out zone2. Stay out of avalanche run out zone

3. Never cross above your partner3. Never cross above your partner

4. Have an escape route planned4. Have an escape route planned

5. Travel in the same route when possible5. Travel in the same route when possible

6. Keep your partner in sight6. Keep your partner in sight

7. Travel to points of safety7. Travel to points of safety

Reducing your riskgood sledding habits

avalanches avoidance


Will I get carried over a cliff?Will I get carried over a cliff?Will I get pinballed in the trees?Will I get pinballed in the trees?Will I get dragged through sharp rocks?Will I get dragged through sharp rocks?Will I be buried?Will I be buried?

Consider the terrain consequences during route selection

avalanches avoidance


Companion/beacon rescue

Backcountry Access − 22Source: AAA

Asphyxiation is the primary causeof avalanche fatalities

companion/beacon rescue

25%

75%


Source: AAA(422 completely buried victims)

If recovered within 15 minutes,chances of survival are almost 92%

At 35 minutes, survival rate drops to 37%

After that, the success rate is extremely low.

…but if you get to them fast enough,you can save them



Source: AAASearch times in 100mx100m area

…and most likely only if you havean avalanche transceiver


Search Method Search Time Searchers

beacon <15 minutes 1 person

search dog 30 minutes 1 trained dog

coarse probe 4 hours 20 person probe line

fine probe 16-20 hours 20 person probe line


• If caught, yell so other people see you. Then close your mouth.

• Try to ride to flanks of avalanche. Get away from sled if you lose control.

• Fight with all of your effort, try to stay on the surface.

• As the snow slows, try to thrust a hand upward above the snow surface.

• Before the snow stops, try to clear an air space in front of your face.

• If buried, do not panic! Stay calm and try to relax.

If an avalanche occursand you are the victim



• Watch the victim(s) as they are carried down the slope.

Look for “last seen point.”

• Make sure it is safe to begin a search.

• Organize the search party.

• Mark the area where the victim was last seen and begin search here. Look for any clues.

• Begin beacon search.

• When victim is located, confirm depth and location with a probe. Dig fast but carefully.

If an avalanche occursand you are a rescuer



1. 1. Avalanche beacon Avalanche beacon follows electronicfollows electronic signal to buried victim signal to buried victim

2. 2. Probe Probe verifies depth and location of verifies depth and location of buried victim buried victim

3. 3. ShovelShovel removes snow removes snow

4. 4. BackpackBackpack to carry your shovel and probe to carry your shovel and probe

What do you need for a rescue?



IASA Avalanche Education Repositorywww.snowiasa.org

www.backcountryaccess.com/education

www.avalanche.org

www.avalanche.ca

Resources

educational resources


Questions?

Avalanche Avoidance and Companion Rescue

backcountry access − 0 avalanche avoidance and companion rescue

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