HAZUS and Hurricane IvanHAZUS and Hurricane IvanModel predictions and Model predictions and measured wind speedsmeasured wind speeds

Greg Gaston Ph.D.Greg Gaston Ph.D.gggaston@una.edugggaston@una.edu

Associate ProfessorAssociate ProfessorGeography Department Geography Department

University of North AlabamaUniversity of North Alabama

Training and Travel supported by a Research Grant Training and Travel supported by a Research Grant from the UNA College of Sciencefrom the UNA College of Science

Ivan: “Alabama’s Hurricane” of 2004

September 2004

September 2004

May 2005...

July 2005...

2005 July

100,000 years of simulated storms...extrapolated from historic storm tracks100,000 years of simulated storms...extrapolated from historic storm tracks

http://www.aoml.noaa.gov/hrd/tcfaq/mh05.jpg

Hurricanes in the Atlantic Basin: 1851-2004http://www.aoml.noaa.gov/hrd/tcfaq/E11.html

What is HAZUS? What is HAZUS?

GIS-based software tools (ArcGIS)GIS-based software tools (ArcGIS) Loss estimation software that Loss estimation software that

estimates physical damage from estimates physical damage from earthquakes, hurricanes, and floodsearthquakes, hurricanes, and floods

Available from FEMA free of charge Available from FEMA free of charge (www.fema.gov/hazus)(www.fema.gov/hazus)

Why HAZUS?Why HAZUS? Earthquakes, floods, and hurricanes Earthquakes, floods, and hurricanes

generate billions of dollars in lossesgenerate billions of dollars in losses

Knowing potential losses:Knowing potential losses:

• Enables better planningEnables better planning

• Allows for improved infrastructure to Allows for improved infrastructure to protect people and reduce economic protect people and reduce economic losseslosses

HAZUS can estimate potential future HAZUS can estimate potential future losseslosses

Damage estimation/responseDamage estimation/responseand planningand planning

The Federal Emergency Management The Federal Emergency Management Agency (FEMA) has spent over $40 Agency (FEMA) has spent over $40 million developing and improving a million developing and improving a model for damage prediction in the model for damage prediction in the built environmentbuilt environment

Originally, only used for earthquake Originally, only used for earthquake damage, the HAZUS MH has been damage, the HAZUS MH has been expanded to include multiple hazards expanded to include multiple hazards (hurricane winds and flooding)(hurricane winds and flooding)

HAZUS-MH Loss Estimation HAZUS-MH Loss Estimation MethodologyMethodology

Earthquake Flood Hurricane

Hurricane Model - HazardHurricane Model - Hazard

90 - 100

100 - 110

110 - 120

120 - 130

130 - 140

140 - 150

150 - 160

Design Peak Gust Hurricane WindSpeeds (mph) In Open Terrain

Track model for Track model for storms affecting the storms affecting the Gulf and Atlantic Gulf and Atlantic coasts, and Hawaiicoasts, and Hawaii

Hurricane wind field Hurricane wind field model developed model developed with NSF fundingwith NSF funding

Regional mappings Regional mappings of land-use to of land-use to surface roughnesssurface roughness

Hurricane Hazard ModelHurricane Hazard Model Storms initiated Storms initiated

in:in: • Atlantic Atlantic • Caribbean Caribbean • Gulf of MexicoGulf of Mexico• Eastern PacificEastern Pacific• Central PacificCentral Pacific

Storm curvatureStorm curvature Multiple land Multiple land

falls falls Changes in Changes in

intensityintensity design wind design wind

speeds in ASCE-speeds in ASCE-7-987-98

Atlantic

CAT 4

CAT 3

CAT 5

880

890

900

910

920

930

940

950

960

970

980

1 10 100 1000Return Period (Years)

Central P

ressure at Landfall

(millibar)

Observed

Modeled

Wind Field ModelWind Field Model Solves full non-linear equations of Solves full non-linear equations of

motion for translating hurricane; then motion for translating hurricane; then establishes parameters for fast running establishes parameters for fast running simulationsimulation• Storm asymmetries Storm asymmetries • Changing sea-surface roughnessChanging sea-surface roughness• Air-sea temperature differenceAir-sea temperature difference• Translation speedsTranslation speeds

Hurricane Model – Building Hurricane Model – Building ClassificationClassification Building components Building components

determine degree of determine degree of damagedamage

1,8841,884 building building classesclasses• Building TypeBuilding Type• Number of storiesNumber of stories• Roof StrapsRoof Straps• Wall ConstructionWall Construction• Roof CoveringRoof Covering• Etc.Etc.

Example: Sensitivity to Wind Example: Sensitivity to Wind SpeedSpeed

±10%

±70%

User Defined (Single Storm) User Defined (Single Storm) Scenario TypeScenario Type 3 options:3 options:

• Define Define manuallymanually

• Import from Import from exported file exported file (other (other HAZUS HAZUS users)users)

• Import Import storm storm advisory advisory from the from the Hurrevac Hurrevac FTP siteFTP site

Questions and AssumptionsQuestions and Assumptions

How well does HAZUS predict peak How well does HAZUS predict peak wind gusts from a hurricane as it wind gusts from a hurricane as it tracks inland?tracks inland?

Working Assumption: As the HAZUS Working Assumption: As the HAZUS model integrates accepted NOAA model integrates accepted NOAA hurricane models (Hurwind, Hursim). hurricane models (Hurwind, Hursim). The accuracy of the wind predictions The accuracy of the wind predictions will be highest very near landfall. will be highest very near landfall. Accuracy will degrade as the storm Accuracy will degrade as the storm tracks inland.tracks inland.

Limitations and CaveatsLimitations and Caveats

Ivan (2004) is the only hurricane Ivan (2004) is the only hurricane examined (for this presentation)examined (for this presentation)

Peak Wind gust data from Alabama Peak Wind gust data from Alabama stationsstations

Data were taken from NOAA’s Data were taken from NOAA’s National Hurricane Center National Hurricane Center http://www.nhc.noaa.gov/2004ivan.shtmlhttp://www.nhc.noaa.gov/2004ivan.shtml

Mesonet Data Stations Regional Airport Weather Stations (ASOS)

Spatial locations...Spatial locations... Spatial location data for each Spatial location data for each

reporting station was collected either reporting station was collected either from Auburn University (Mesonet from Auburn University (Mesonet stations) or from the AirNav website stations) or from the AirNav website for ASOS sites.for ASOS sites.

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KALX

KBHM

K3A1

KDHN

K4A9

KOZR

KGAD

KHSV KMDQ

KMXF

KMOB

KMGM

KMSL

KTOI

KTCL

OPNA1

GCSA1

C0168

RLDM6

GBYA1

Stations used to evaluate Ivan’s Wind Gusts

Ivan’s Actual Track...

Re-formed and back into Texas

CITYDESIGNATOR

DATE/TIME_

peak gusts MPH

modeled values

model - actual

percent_difference

Alexander Cit KALX 16/1500 41 82 41 0.50

Birmingham KBHM 17/0053 48 82 34 0.41

Covington OPNA1 16/1022 67 119 52 0.44

Cullman K3A1 16/1740 45 59 14 0.24

Dothan KDHN 16/1900 54 66 12 0.18

Fairhope GCSA1 16/0418 72 146 74 0.50

Florence * C0168 17/0050 43 40 -3 -0.06

Ft.Payne * K4A9 16/1920 52 40 -12 -0.29

Ft. Rucker KOZR 16/0955 44 75 31 0.42

Gadsden KGAD 16/1735 43 62 19 0.31

Grand Bay GBYA1 16/0517 71 130 59 0.45

Huntsville KHSV 16/2153 46 51 5 0.10

Huntsville * KMDQ 16/2242 40 40 0 -0.01

Lauderdale RLDM6 16/1113 54 83 29 0.35

Maxwell AFB KMXF 16/1755 66 90 24 0.27

Mobile KMOB 16/0644 75 137 62 0.45

Montgomery KMGM 16/1353 58 90 33 0.36

Muscle Shoals * KMSL 16/2110 46 40 -6 -0.15

Semmes SEMA1 16/0500 59 137 78 0.57

Troy KTOI 16/1128 43 81 38 0.47

Tuscaloosa KTCL 16/1453 49 79 30 0.37

Size of the circle at each station indicates the magnitude of the difference between the model prediction and the observed wind speeds

Magnitude of difference between model prediction and station records and distance from the coast.

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0.57

0.45

0.500.44

0.42

0.47

0.18

0.36

0.270.35

0.37

0.41

0.50

0.31

-0.29

-0.01

0.100.24

-0.15

-0.06

% Difference between model predictions and observed peak gusts.

Color bands indicate 50 mile increments from the coast.

CITYDESIGNATOR model - actual percent_difference dist to coast Miles

Alexander Cit KALX 41 0.50 180

Birmingham KBHM 34 0.41 219

Covington OPNA1 52 0.44 44

Cullman K3A1 14 0.24 268

Dothan KDHN 12 0.18 76

Fairhope GCSA1 74 0.50 2

Florence * C0168 -3 -0.06 305

Ft.Payne * K4A9 -12 -0.29 296

Ft. Rucker KOZR 31 0.42 67

Gadsden KGAD 19 0.31 255

Grand Bay GBYA1 59 0.45 9

Huntsville KHSV 5 0.10 296

Huntsville * KMDQ 0 -0.01 315

Lauderdale RLDM6 29 0.35 122

Maxwell AFB KMXF 24 0.27 138

Mobile KMOB 62 0.45 13

Montgomery KMGM 33 0.36 132

Muscle Shoals * KMSL -6 -0.15 294

Semmes SEMA1 78 0.57 13

Troy KTOI 38 0.47 102

Tuscaloosa KTCL 30 0.37 183

% diff and distance from coast

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400

-0.40 -0.30 -0.20 -0.10 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70

% difference

mile

s fr

om c

oast

% Difference and Distance from Coast

50 5 0.4820100 3 0.3567150 2 0.3150200 2 0.4350250 2 0.3600300 5 -0.0320

Distance Number of stations Average Error

Analysis and General Analysis and General Observations:Observations:

From these data HAZUS model over-From these data HAZUS model over-estimates wind speed.estimates wind speed.

Stations closer to the coast have a greater Stations closer to the coast have a greater over-estimation.over-estimation.

At distances 200-300 miles inland, the At distances 200-300 miles inland, the agreement between the model and actual agreement between the model and actual values is very high.values is very high.

In the case of Ivan, the model results are In the case of Ivan, the model results are in many cases twice as high as the actual in many cases twice as high as the actual winds measured.winds measured.

Is Ivan a special case?

Does the HAZUS model accurately predict damage/loss in spite of over estimating wind velocity?

Peak Wind Gusts

Final Hurrevac track (red line)

Black line... Final corrected track

““... Final Corrected Track...”... Final Corrected Track...”

By using the parameters contained in By using the parameters contained in the NWS forecast advisory with no the NWS forecast advisory with no modification, HAZUS overestimates modification, HAZUS overestimates wind velocity. wind velocity.

An experimental NWS model H*wind An experimental NWS model H*wind provides a better solutionprovides a better solution

Final Corrected track Final Corrected track uses H*WIND uses H*WIND landfall parameters landfall parameters and NHC track and NHC track coupled with coupled with surface wind speed surface wind speed and pressure and pressure measurements from measurements from C-MAN stations, C-MAN stations, Buoys, ASOS and Buoys, ASOS and FCMP tower dataFCMP tower data T1 - Adjusted for Terrain

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Comparison of NHC and H*WIND Comparison of NHC and H*WIND Wind Speeds – Hurricane IvanWind Speeds – Hurricane Ivan

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9/12/04 0:00 9/13/04 0:00 9/14/04 0:00 9/15/04 0:00 9/16/04 0:00 9/17/04 0:00

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Hurricane Ivan Wind Field Hurricane Ivan Wind Field Validation ExampleValidation Example

T1

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Model results from the “Final Corrected Track” released just after landfall... Much higher accuracy

Conclusions...Conclusions... The model results for Ivan using the The model results for Ivan using the

hurrevac track/storm parameter data over hurrevac track/storm parameter data over estimate the winds by as much as 57%estimate the winds by as much as 57%

The patterns of over estimation as related The patterns of over estimation as related to the coast are virtually to the coast are virtually unchanged...model predictions are unchanged...model predictions are generally significantly over-estimated near generally significantly over-estimated near the coast.the coast.

The methodology for creating a The methodology for creating a final track needs to be fully final track needs to be fully documented!!documented!!

Modified ConclusionsModified Conclusions

Using the same methodology with Charley, Using the same methodology with Charley, Francis, and Jeanne from 2004 on the NWS Francis, and Jeanne from 2004 on the NWS track/storm parameters (not the adjusted track/storm parameters (not the adjusted final track)final track)

The results are consistent in that the The results are consistent in that the tendency to overestimate wind field can tendency to overestimate wind field can be clearly seen in the resultsbe clearly seen in the results

However, the increase in accuracy as a However, the increase in accuracy as a function of distance from the coast is no function of distance from the coast is no longer apparent.longer apparent.

Windfield Speed

0

1 - 65

66 - 76

77 - 86

87 - 96

97 - 105

106 - 116

117 - 126

127 - 135

136 - 150

Magnitude of Difference

1 - 3

4 - 14

15 - 18

19 - 26

27 - 43

Actual Track

All speed given in miles/ hour.

Frances 2004Final Track and Windfield

Difference between station observation and predicted windfield

Windfield Speed

0

1 - 65

66 - 80

81 - 93

94 - 103

104 - 115

116 - 128

129 - 143

144 - 158

159 - 171

Magnitude of Difference

0 - 5

6 - 10

11 - 18

19 - 74

75 - 82

Actual Track

All speed given in miles/ hour.

J eanne 2004Final Track and Windfield

Difference between station observation and predicted windfield

FinallyFinally

HAZUS MH appears to do an HAZUS MH appears to do an acceptable job of modeling wind acceptable job of modeling wind speeds and thus can create accurate speeds and thus can create accurate estimations of damage and loss from estimations of damage and loss from hurricane windshurricane winds

The best data for estimation comes The best data for estimation comes from the “final corrected track” from the “final corrected track” (which is now strongly recommended (which is now strongly recommended by FEMA)by FEMA)