Lesson 1: Introducing the Enhanced Fujita Scale Dan McCarthy ( NWS SPC) and Jim LaDue (NWS WDTB)
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Transcript of Lesson 1: Introducing the Enhanced Fujita Scale Dan McCarthy ( NWS SPC) and Jim LaDue (NWS WDTB)
Lesson 1: Introducing the Lesson 1: Introducing the Enhanced Fujita ScaleEnhanced Fujita Scale
Lesson 1: Introducing the Lesson 1: Introducing the Enhanced Fujita ScaleEnhanced Fujita Scale
Dan McCarthy ( NWS SPC)Dan McCarthy ( NWS SPC)
and and
Jim LaDue (NWS WDTB)Jim LaDue (NWS WDTB)
Goal and Scope of TrainingGoal and Scope of TrainingGoal and Scope of TrainingGoal and Scope of Training
• The Goal of this Training is to effectively integrate The Goal of this Training is to effectively integrate the EF-Scale into the post storm damage the EF-Scale into the post storm damage assessment.assessment.
• Two lessons, each followed by a quizTwo lessons, each followed by a quiz
– Comparison of the EF and F-ScaleComparison of the EF and F-Scale
– Using the EF-Scale to estimate tornado strengthUsing the EF-Scale to estimate tornado strength
MotivationMotivationMotivationMotivation
• EF-Scale to be used by the NWS starting 01 Feb, EF-Scale to be used by the NWS starting 01 Feb, 20072007
• More complex than F-ScaleMore complex than F-Scale
Lesson 1: Learning ObjectivesLesson 1: Learning ObjectivesLesson 1: Learning ObjectivesLesson 1: Learning Objectives
1.1. Understand why the EF-Scale was created Understand why the EF-Scale was created
2.2. Identify the methodology in creating the EF-Scale. Identify the methodology in creating the EF-Scale.
3.3. Understand the structure of the EF-ScaleUnderstand the structure of the EF-Scale
4.4. Identify differences between the EF- and F-ScaleIdentify differences between the EF- and F-Scale
5.5. Understand the strengths of the EF-ScaleUnderstand the strengths of the EF-Scale
6.6. Understand the limitations of the EF-ScaleUnderstand the limitations of the EF-Scale
Performance ObjectivePerformance ObjectivePerformance ObjectivePerformance Objective
• Apply the strengths and limitations of the EF-Scale Apply the strengths and limitations of the EF-Scale when rating damage produced by a tornadowhen rating damage produced by a tornado
Why the EF-Scale was createdWhy the EF-Scale was createdWhy the EF-Scale was createdWhy the EF-Scale was created
• Need more Need more damage damage indicatorsindicators
• recalibrate windsrecalibrate winds associated with F-scale associated with F-scale ratingsratings
• better better correlate wind correlate wind and ratingand rating
• account for account for construction construction variabilityvariability
• Flexibility, Extensibility, Flexibility, Extensibility, ExpandabilityExpandability
Evidence indicates a well Evidence indicates a well constructed house can be blown constructed house can be blown away by winds much less than away by winds much less than 260 mph 260 mph ((Phan and Simiu,2003)..
Objectives: 1, Why the EF-Scale?
The framed house is one of only The framed house is one of only a few F-scale damage a few F-scale damage indicators.indicators.
EF-Scale history: Steering CommitteeEF-Scale history: Steering CommitteeEF-Scale history: Steering CommitteeEF-Scale history: Steering Committee
Organize a Steering Committee (2001)
Jim McDonald - TTUJoe Schaefer - SPC
Brian Smith, NWS OAX
Michael Riley - NIST
Objectives: 2, Methodology
Kishor Mehta -TTU
Don Burgess – NSSL
The Steering Committee Organizes a ForumThe Steering Committee Organizes a ForumThe Steering Committee Organizes a ForumThe Steering Committee Organizes a Forum
• Led by Wind Science Led by Wind Science and Engineering and Engineering Center, Texas Tech Center, Texas Tech University, 7-8 March University, 7-8 March 20012001
• ObjectivesObjectives– Representative group of Representative group of
usersusers– ID key issuesID key issues– Make recommendationsMake recommendations– Develop a strategyDevelop a strategy
Objectives: 2, Methodology
The forum identifies EF-Scale development The forum identifies EF-Scale development strategiesstrategies
The forum identifies EF-Scale development The forum identifies EF-Scale development strategiesstrategies
• Identify additional Damage Indicators (DI)sIdentify additional Damage Indicators (DI)s• Correlate damage to wind speedCorrelate damage to wind speed
– Degrees of Damage (DOD) for each DIDegrees of Damage (DOD) for each DI
• Preserve the historical databasePreserve the historical database• Seek input from usersSeek input from users• Maximize usabilityMaximize usability
Objectives: 2, Methodology
EF-Scale Damage Indicators (DIs)EF-Scale Damage Indicators (DIs)EF-Scale Damage Indicators (DIs)EF-Scale Damage Indicators (DIs)
• 28 DIs were identified by the Steering Committee28 DIs were identified by the Steering Committee• DIs and DODs can be added or modifiedDIs and DODs can be added or modified• Each DI has several Degrees of Damage (DOD) Each DI has several Degrees of Damage (DOD)
Objectives: 2, methodology; 3, EF-Scale structure
Framed house Single wide mobile home Small Retail Building
28 Damage Indicators28 Damage Indicators28 Damage Indicators28 Damage Indicators
Objectives: 3, EF-Scale structure
Residences
Commercial/retail structures
Schools
Professional buildings
Metal buildings/canopies
Towers/poles
Vegetation
DOD Damage Description EXP LB UB
1 Threshold of visible damage ? ? ?
2 Loss of roof covering material (<20%), gutters and/or awning; loss of vinyl or metal siding
3 Broken glass in doors and windows
4 Uplift of roof deck and loss of significant roof covering material (>20%); collapse of chimney; garage doors collapse inward or outward; failure of porch or carport
5 Entire house shifts off foundation
6 Large sections of roof structure removed; most walls remain standing
7 exterior walls collapsed
8 Most walls collapsed except small interior rooms.
9 All walls collapsed
10 Destruction of engineered and/or well constructed residence; slab swept clean
Degrees of DamageDegrees of DamageDegrees of DamageDegrees of Damage
DOD for a Framed House, FR12 or DOD2
Objectives: 2, methodology; 3, EF-Scale structure
Reason behind an upper and lower bound Reason behind an upper and lower bound wind speedwind speed
Reason behind an upper and lower bound Reason behind an upper and lower bound wind speedwind speed
EXP: Design exhibits typical
construction
One, Two Family House
0
50
100
150
200
250
1 2 3 4 5 6 7 8 9 10
DOD
WIn
d S
peed (m
ph)
EXP
LB
UB
Win
d S
pee
d (
mp
h)
Objectives: 2, methodology; 3, EF-Scale structure
Reason behind an upper and lower bound Reason behind an upper and lower bound wind speed (contd)wind speed (contd)
Reason behind an upper and lower bound Reason behind an upper and lower bound wind speed (contd)wind speed (contd)
EXP: Design exhibits typical
construction
UB: Design exceeds codes for typical US home,
better than average load path.
LB: Design fails to meet US building
codes, poor maintenance
and/or load path
One, Two Family House
0
50
100
150
200
250
1 2 3 4 5 6 7 8 9 10
DOD
WIn
d S
peed (m
ph)
EXP
LB
UB
Win
d S
pee
d (
mp
h)
Objectives: 2, methodology; 3, EF-Scale structure
How the winds were derived for each DODHow the winds were derived for each DODHow the winds were derived for each DODHow the winds were derived for each DOD
• Possible CandidatesPossible Candidates– Structural analysis to determine resistance and Structural analysis to determine resistance and
theoretical failure modestheoretical failure modes– Simulation of tornado winds to produce structural
damage – Expert Elicitation
• Chosen method?– Expert Elicitation
Objectives: 2, EF-Scale methodology
Chosen Experts:Greg Forbes – Meteorologist, TWCDon Burgess – Meteorologist, NSSLDoug Smith – Engineer, TTUTim Reinhold – Engineer, Clemson UniversityTom Smith – Architect, ConsultantTim Marshall – Meteorologist/Engineer, Haag Engineers
Derive Wind Speeds by Expert Elicitation Derive Wind Speeds by Expert Elicitation Derive Wind Speeds by Expert Elicitation Derive Wind Speeds by Expert Elicitation
Objectives: 2, EF-Scale methodology
Describe the DIs and
DODs and present to
experts
Train the experts in elicitation process
Experts individually
estimate wind speeds for each
DOD
Mehta and McDonald analyze results and
present to experts for review
Experts revise their wind speeds
Iterate again
Present final estimates to
forum for review
Degrees of DamageDegrees of DamageDegrees of DamageDegrees of Damage
DOD Damage Description EXP LB UB
1 Threshold of visible damage 63 53 80
2 Loss of roof covering material (<20%), gutters and/or awning; loss of vinyl or metal siding 79 63 97
3 Broken glass in doors and windows 96 79 114
4 Uplift of roof deck and loss of significant roof covering material (>20%); collapse of chimney; garage doors collapse inward or outward; failure of porch or carport
97 81 116
5 Entire house shifts off foundation 121 103 141
6 Large sections of roof structure removed; most walls remain standing 122 104 142
7 exterior walls collapsed 132 113 153
8 Most walls collapsed except small interior rooms. 152 127 178
9 All walls collapsed 170 142 198
10 Destruction of engineered and/or well constructed residence; slab swept clean 200 162 220
Objectives: 3, EF-Scale structure
Example DODs for a Framed House DI (FR12 or DI2)
Note some consecutive DODs have larger overlap than others
DOD Damage Description EXP LB UB
1 Threshold of visible damage 63 53 80
2 Loss of roof covering material (<20%), gutters and/or awning; loss of vinyl or metal siding 79 63 97
3 Broken glass in doors and windows 96 79 114
4 Uplift of roof deck and loss of significant roof covering material (>20%); collapse of chimney; garage doors collapse inward or outward; failure of porch or carport
97 81 116
5 Entire house shifts off foundation 121 103 141
6 Large sections of roof structure removed; most walls remain standing 122 104 142
7 exterior walls collapsed 132 113 153
8 Most walls collapsed except small interior rooms. 152 127 178
9 All walls collapsed 170 142 198
10 Destruction of engineered and/or well constructed residence; slab swept clean 200 162 220
Degrees of DamageDegrees of DamageDegrees of DamageDegrees of Damage
DOD Damage Description EXP LB UB
1 Threshold of visible damage 63 53 80
2 Loss of roof covering material (<20%), gutters and/or awning; loss of vinyl or metal siding 79 63 97
3 Broken glass in doors and windows 96 79 114
4 Uplift of roof deck and loss of significant roof covering material (>20%); collapse of chimney; garage doors collapse inward or outward; failure of porch or carport
97 81 116
5 Entire house shifts off foundation 121 103 141
6 Large sections of roof structure removed; most walls remain standing 122 104 142
7 exterior walls collapsed 132 113 153
8 Most walls collapsed except small interior rooms. 152 127 178
9 All walls collapsed 170 142 198
10 Destruction of engineered and/or well constructed residence; slab swept clean 200 162 220
Example DODs for a Framed House DI (FR12 or DI2)
Note some consecutive DODs have larger overlap than others
One, Two Family House
0
50
100
150
200
250
1 2 3 4 5 6 7 8 9 10
DOD
WIn
d S
peed (m
ph)
EXP
LB
UB
Win
d S
pee
d (
mp
h)
Objectives: 2, methodology; 3, EF-Scale structure
Relating the F-scale with the EF-ScaleRelating the F-scale with the EF-ScaleRelating the F-scale with the EF-ScaleRelating the F-scale with the EF-Scale
• Need of historical Need of historical continuitycontinuity
• 22ndnd set of experts set of experts assigned F-scale assigned F-scale ratings to the same ratings to the same damage damage descriptionsdescriptions
• Median F-scale Median F-scale wind speeds wind speeds compared to that of compared to that of expected EF-Scale expected EF-Scale wind speedswind speeds
Objectives: 2, methodology; 4, EF vs F-Scale
The F-Scale wind speed was converted from the fastest ¼ mi to a 3 sec gust.
Bill Bunting – NWSFO – Fort Worth, TexasBrian Peters – NWSFO – Calera, AlabamaJohn Ogren – NWSFO – Indianapolis, IndianaDennis Hull – NWSFO – Pendleton, OregonTom Matheson – NWSFO – Wilmington, North CarolinaBrian Smith – NWSFO – Valley, Nebraska
Y = 0.6246x + 36.393R2 = 0.9118
F5 to EF5 threshold wind speed
F-Scale Converted to EF-Scale F-Scale Converted to EF-Scale
F ScaleF Scale Wind SpeedWind Speed EF-ScaleEF-Scale Wind SpeedWind Speed
F0F0 45-7845-78 EF0EF0 65-8565-85
F1F1 79-11779-117 EF1EF1 86-10986-109
F2F2 118-161118-161 EF2EF2 110-137110-137
F3F3 162-209162-209 EF3EF3 138-167138-167
F4F4 210-261210-261 EF4EF4 168-199168-199
F5F5 262-317262-317 EF5EF5 200-234200-234
Wind speeds in mph, 3-second gust
Objectives: 3, EF-Scale structure; 4, EF vs F-Scale
DOD to Wind Speed to EF-ScaleDOD to Wind Speed to EF-Scale
EF-Scale CategoriesEF-Scale Categories Wind Speed RangesWind Speed Ranges
EF0EF0 65-8565-85
EF1EF1 86-11086-110
EF2EF2 111-135111-135
EF3EF3 136-165136-165
EF4EF4 166-200166-200
EF5EF5 >200>200
Objectives: 3, EF-Scale structure
Wind speeds in mph, 3-second gust
Comparing Beaufort, F, and Mach ScalesComparing Beaufort, F, and Mach ScalesComparing Beaufort, F, and Mach ScalesComparing Beaufort, F, and Mach Scales
1 2 3 4 5 6 7 8 9 10 11 120Beaufort Scale
1 2 3 4 5 6 7 8 90 10 11 12Fujita Scale
0.6 1.0
Mach Scale
B1 B3B5
B7B9
B11
F0F1
F2
F3
F4
F5
F12M1.0
M0.6
M0.7
M0.8
B17
Beaufort: V = 1.870B3/2 mph F – scale: V = 14.1(F+2)3/2 mphMach scale: V = (742 +1.3)M mph
These scales have wind speed defined first, impacts/damage were assigned to wind speeds.
Objectives: 3, EF-Scale structure; 4, EF vs F-Scale
Comparing F and EF-ScalesComparing F and EF-ScalesComparing F and EF-ScalesComparing F and EF-Scales
1 2 3 4 5 6 7 8 9 10 11 120Beaufort Scale
1 2 3 4 5 6 7 8 90 10 11 12Fujita Scale
0.6 1.0
Mach Scale
B1 B3B5
B7B9
B11
F0F1
F2
F3
F4
F5
F12M1.0
M0.6
M0.7
M0.8
B17
EF0EF1
EF2EF3
EF4
EF5
0 1 2 3 4 5
EF-Scale
The EF-Scale is a damage scale: speeds were estimated from the damage
Objectives: 3, EF-Scale structure; 4, EF vs F-Scale
DOD to Wind Speed to EF-Scale questionDOD to Wind Speed to EF-Scale questionDOD to Wind Speed to EF-Scale questionDOD to Wind Speed to EF-Scale questionDOD Damage Description – Framed House EXP LB UB
1 Threshold of visible damage 63 53 80
2 Loss of roof covering material (<20%), gutters and/or awning; loss of vinyl or metal siding
79 63 97
3 Broken glass in doors and windows 96 79 114
4 Uplift of roof deck and loss of significant roof covering material (>20%); collapse of chimney; garage doors collapse inward or outward; failure of porch or carport
97 81 116
5 Entire house shifts off foundation 121 103 141
6 Large sections of roof structure removed; most walls remain standing 122 104 142
7 exterior walls collapsed 132 113 153
8 Most walls collapsed except small interior rooms. 152 127 178
9 All walls collapsed 170 142 198
10 Destruction of engineered and/or well constructed residence; slab swept clean
200 162 220
Objectives: 3, EF-Scale structure
Quiz: What DOD best corresponds with this damage?
DOD to Wind Speed to EF-Scale reviewDOD to Wind Speed to EF-Scale reviewDOD to Wind Speed to EF-Scale reviewDOD to Wind Speed to EF-Scale reviewDOD Damage Description – Framed House EXP LB UB
1 Threshold of visible damage 63 53 80
2 Loss of roof covering material (<20%), gutters and/or awning; loss of vinyl or metal siding
79 63 97
3 Broken glass in doors and windows 96 79 114
4 Uplift of roof deck and loss of significant roof covering material (>20%); collapse of chimney; garage doors collapse inward or outward; failure of porch or carport
97 81 116
5 Entire house shifts off foundation 121 103 141
6 Large sections of roof structure removed; most walls remain standing 122 104 142
7 exterior walls collapsed 132 113 153
8 Most walls collapsed except small interior rooms. 152 127 178
9 All walls collapsed 170 142 198
10 Destruction of engineered and/or well constructed residence; slab swept clean
200 162 220
Objectives: 3, EF-Scale structure
Expected wind 97 mph
EF-Scale answerEF-Scale answer
EF-Scale CategoriesEF-Scale Categories Wind Speed RangesWind Speed Ranges
EF0EF0 65-8565-85
EF1EF1 86-11086-110
EF2EF2 111-135111-135
EF3EF3 136-165136-165
EF4EF4 166-200166-200
EF5EF5 >200>200
Wind Speed in mph, 3-Second gust
Objectives: 3, EF-Scale structure
Strengths of EF-ScaleStrengths of EF-ScaleStrengths of EF-ScaleStrengths of EF-Scale
• EF-ScaleEF-Scale– 28 DIs28 DIs
– Accounts for differences of Accounts for differences of structural integrity within a DIstructural integrity within a DI
– Wind speeds determined from Wind speeds determined from damagedamage
– Continuity from the F-scale Continuity from the F-scale
– Expandibility, Flexibility, Expandibility, Flexibility, ExtensibilityExtensibility
• F ScaleF Scale– Only a Couple DIsOnly a Couple DIs
– No accounting for differences of No accounting for differences of structural integrity within a DIstructural integrity within a DI
– Wind speeds not derived from Wind speeds not derived from damagedamage
Objectives: 5, EF-Scale strengths
EF-Scale limitationsEF-Scale limitationsEF-Scale limitationsEF-Scale limitations
• Change in scale may introduce artifacts into the Change in scale may introduce artifacts into the historical recordhistorical record
• Complicated Complicated • Wind speeds subject to change for each ratingWind speeds subject to change for each rating• No function relating wind speed to ratingNo function relating wind speed to rating• Debate continues about wind speed assignmentsDebate continues about wind speed assignments
Objectives: 6, EF-Scale limitations
Summary: Lesson 1Summary: Lesson 1Summary: Lesson 1Summary: Lesson 1
• EF-Scale created to provide more DIs, more EF-Scale created to provide more DIs, more realistic wind speedsrealistic wind speeds
• EF-Scale winds were estimated using expert EF-Scale winds were estimated using expert elicitationelicitation
• EF-Scale contains 28 DIs, each with several DODs EF-Scale contains 28 DIs, each with several DODs ranging from first damage to destruction or if the ranging from first damage to destruction or if the estimated wind speeds correspond to an EF 5 estimated wind speeds correspond to an EF 5 rating.rating.
• EF-Scale winds significantly lower than F-scale for EF-Scale winds significantly lower than F-scale for EF (F3) and higherEF (F3) and higher
• EF-Scale is complicated requiring a longer time for EF-Scale is complicated requiring a longer time for familiarizationfamiliarization
Objectives: 1-6
References and suggested readingReferences and suggested readingReferences and suggested readingReferences and suggested reading
McDonald, J.R. and K.C. Mehta, 2001: Summary report of the Fujita Scale forum. Wind Science and Engineering, Texas Tech University, Lubbock, TX, 36 pp.
Phan, L.T. and E. Simiu, 1998: The Fujita tornado intensity scale: a critique based on observations of the Jarrell tornado of May 27, 1997. NIST Tech. Note 1426, U.S. Department of Commerce, Gaithersburg, MD, 20 pp.
SSHAC, 1997: Recommendations for probabilistic seismic hazard analysis: guidelines on uncertainty and use of experts, NUREG/CR6372, UCRL-ID-122160, Vol. I, Lawrence Livermore National Laboratory, Livermore, CA, 131 pp.
Suggested reading: A Recommendation for the Enhanced Fujita Scale: http://
www.spc.noaa.gov/efscale/
In Lesson 2In Lesson 2In Lesson 2In Lesson 2
• Lesson 2 provides you a chance to use the EF-Lesson 2 provides you a chance to use the EF-Scale on some damage tracksScale on some damage tracks
ContactsContactsContactsContacts
• If you have any questions about this lesson, contactIf you have any questions about this lesson, contact– Jim LaDue, Jim LaDue, [email protected]@noaa.gov– Dan McCarthy, [email protected] McCarthy, [email protected]