understanding and preparing for severe windstorms in 2011 and beyond
DESCRIPTION
UNDERSTANDING AND PREPARING FOR SEVERE WINDSTORMS IN 2011 AND BEYOND. A PRIMER OF KNOWLEDGE THAT CAN MULTIPLY AND SPILL OVER FOR THE BENEFIT OF MILLIONS. Walter Hays, Global Alliance for Disaster Reduction, University of North Carolina, USA. - PowerPoint PPT PresentationTRANSCRIPT
UNDERSTANDING AND PREPARING FOR SEVERE
WINDSTORMSIN 2011 AND BEYOND
A PRIMER OF KNOWLEDGE THAT CAN MULTIPLY AND SPILL OVER FOR THE BENEFIT OF MILLIONS
Walter Hays, Global Alliance for Disaster Reduction, University of
North Carolina, USA
SEVERE WINDSTORMS TORNADOES,
HURRICANES, TYPHOONS, AND CYCLONES
THE PHYSICS OF SEVERE WINDSTORMS
SEVERE WINDSTORMS:TORNADOESHURRICANESTYPHOONSCYCLONES
BASIC PRINCIPLES OF PHYSICS UNDERPINNING WINDSTORMS
• HEAT AND HEAT FLOW
• PRESSURE AND PRESSURE FLOW
• GRAVITY FIELD
• KINETIC ENERGY
• POTENTIAL ENERGY
SEVERE WINDSTORMS TORNADOES
OCCUR OVER LAND AS THE RESULT OF INTERACTIONS OF
THE SUN, ATMOSPHERE, LITHOSPHERE, AND
BIOSPHERE
TORNADOE SEASON
• The peak tornado season is late winter through midsummer,….
• But tornadoes can happen any time of the year when the atmospheric conditions are right.
TORNADO ALLEY
• ALTHOUGH TORNADOES HAVE OCCURRED IN EVERY STATE, THEY OCCUR MOST FREQUENTLY IN “TORNADO ALLEY,” WHICH INCLUDES PARTS OF: TEXAS, OKLAHOMA, ARKANSAS, TENNESSEE, NEBRASKA, KANSAS, MISSOURI, ILLINOIS, AND IOWA.
THE PHYSICS OF TORNADOES
• TORNADOES ARE CAUSED BY THE COLLISION OF DESCENDING COLD AIR MASSESS COMING FROM THE NORTH AND ASCENDING WARM AIR MASSES COMING FROM THE SOUTH.
THE PHYSICS OF TORNADOES
• THE COLLISION CREATES A FUNNEL OF HIGH-VELOCITY WIND THAT IS VERY DESTRUCTIVE AS IT “TOUCHES DOWN” ONE OR MORE TIMES ALONG A LONG, NARROW (TYPICALLY 10-100 M) PATH.
PHYSICS OF A TORNADO
HAZARDS OF A TORNADO (AKA POTENTIAL DISASTER AGENTS)
• WIND: SPEEDS CAN REACH 500 KM/HR (300 MI/HR)
• THUNDER, LIGHTNING, AND HEAVY PRECIPITATION E EXTREME
• HAIL CAN BE VERY DAMAGING
THIRTY TO FORTY TORNADOES STRIKE FIVE
SOUTHERN STATES
Mississippi, Alabama, Arkansas, Kentucky, and Tennessee impacted
54 dead
FEBRUARY 5, 2008
MAP
TORNADOE SEASON AFFECTED BY LA NINA
• This tornado outbreak could be a consequence of La Nina, the cooling of the Pacific Ocean, which can cause changes in weather patterns around they world.
WARNING• The people had ample warning to get
out of harm’s way and take cover, …• But some of the warning sirens did not
work.
A TORNADO TOUCHES DOWN NEAR ATKINS, ARKANSAS
DEVASTATION NEAR ATKINS, ARKANSAS
DEVASTATION NEAR ATKINS, ARKANSAS
DEVASTATION NEAR ATKINS, ARKANSAS
COLLAPSE OF WAREHOUSE IN SOUTH HAVEN, MS
COLLAPSE OF WALL IN SHOPPING MALL: MEMPHIS, TN
A FIRE BROKE OUT IN A NATURAL GAS PUMPING STATION:
HARTSVILLE, TN
SEVERE THUNDERSTORM SYSTEM SEVERE THUNDERSTORM SYSTEM SPAWNS TORNADOES IN TEXAS:SPAWNS TORNADOES IN TEXAS:APRIL 24, 2008APRIL 24, 2008
A SUPERCELL
THE FUNNEL
IMPACTS IN WEST AND NORTH TEXAS
•WORST DAMAGE NEAR FT WORTH, TX WITH LOSSES ESTIMATED AT $35 MILLION•WIND SPEED REACHED 116 KM/HR (70 MI HR)
IMPACTS IN WEST AND NORTH TEXAS
•HEAVY RAIN FALL CAUSED POWER OUTAGES AND MINOR FLOODING•BASEBALL-SIZED HAIL
WIND DAMAGE
TORNADOES STRIKE IOWA AND MINNESOTA
Continuation of deadliest tornado season in a decadeAccompanied by large hailMay 25, 2008
HUGO, MINNESOTA: DEBRIS MARKS STORM'S PATH
PARKERSBURG, IOWA: DAMAGE
PARKERSBURG, IOWA: LOOKING FOR SURVIVORS
SEVERE WINDSTORMS HURRICANES, TYPHOONS, CYCLONES
CREATED IN THE WARM WATER OF OCEANS AS THE RESULT OF INTERACTIONS OF
THE SUN, ATMOSPHERE, HYDROSPHERE, ATMOSPHERE,
LITHOSPHERE, AND BIOSPHERE
HURRICANES
• In the Atlantic, Caribbean, Gulf of Mexico, and Eastern Pacific areas cyclonic tropical storms with well-formed central “eyes” and with wind speeds above 74 mph are referred to as HURRICANES.
PHYSICS: HURRICANES
TYPHOONS
• The exact same phenomenon, with clockwise rotation about the eye, in the Western Pacific Ocean region is called a TYPHOON.
PHYSICS OF A TYPHOON
SEVERE WINDSTORMS: CYCLONES
• The exact same phenomenon in the Indian Ocean region is called a CYCLONE.
WIND AND WATER PENETRATE BUILDING ENVELOPE
SEVEREWINDSTORMS
UPLIFT OF ROOF SYSTEM
FLYING DEBRIS PENETRATES WINDOWS
STORM SURGE AND HEAVY PRECIPITATION
IRREGULARITIES IN ELEVATION AND PLAN
POOR WORKMANSHIP
IGNORING NON-STRUCTURAL ELEMENTS
CAUSES OF RISK
CASE HISTORIES
HAZARDS OF A HURRICANE, TYPHOON, OR
CYCLONE
THE PHYSICAL PHENOMENA ASSOCIATED WITH A LONG, OCEANIC
TRAVEL PATH AND EVENTUAL LANDFALL
HAZARDS OF A HURRICANE/TYPHOON
(AKA POTENTIAL DISASTER AGENTS)
• WIND FIELD (COUNTER CLOCKWISE OR CLOCKWISE DIRECTION; CAT 1 (55 mph) TO CAT 5 (155 mph or greater)
• STORM SURGE• HEAVY PRECIPITATION• LANDSLIDES (MUDFLOWS)• COSTAL EROSION• TORNADOES (SOMETIMES)
“SEVERE WINDSTORMS ARE LABORATORIES”
EACH PAST EVENT PROVIDES VALUABLE LESSONS FOR POLICY
ON DISASTER RISK REDUCTION
1325+ HURRICANES: DYNAMIC LABORATORIES FOR LEARNING
• EACH HURRICANE HAS IMPORTANT TECHNICAL AND POLITICAL LESSONS THAT CAN BE INTEGRATED INTO DISASTER RISK REDUCTION. POLICY
2005: A RECORD HURRICANE SEASON
• Twenty-eight named storms occurred during the 2005 season.
• Over $100 billion in losses.
LESSONS LEARNED FROM ALL SEVERE WINDSTORMS
• RECOVERY TAKES LONGER AND COSTS MORE THAN EXPECTED.
LESSONS LEARNED FROM ALL SEVERE WINDSTORMS
• EVACUATION IS A COMPLEX ENDEAVOR THAT IS NOT ONLY COSTLY, BUT REQUIRES SUPERIOR PRIOR PLANNING.
LESSONS LEARNED FROM ALL SEERE WINDSTORMS
• TIMELY COMMUNICATION OF CRITICAL INFORMATION IMPROVES:
• MASS EVACUATIONS AND COMMUNITY PREPAREDNESS
LESSONS LEARNED FROM ALL SEVERE WINDSTORMS
• STORM SURGE IS THE PRIMARY “KILLER “ IN HURRICANES, TYPHOONS, AND CYCLONES.
LESSONS LEARNED FROM ALL SEVERE WINDSTORMS
• HIGH VELOCITY WIND LIFTS THE ROOFS OFF OF BUILDINGS AND IS A KILLER IN TORNADOES AS WELL AS IN HURRICANES AND TYPHOONS.
LESSONS LEARNED FROM ALL SEVERE WINDSTORMS
• HIGH VELOCITY WIND AND PRESSURE CHANGES CAUSE BUILDINGS WITH INADEQUATE ENGINEERING DESIGN TO COLLAPSE.
LESSONS LEARNED FROM ALL SEVERE WINDSTORMS
• HEAVY PRECIPITATION, A TYPICAL OCCURRENCE, WILL FLOOD LOW-LYING AREAS ALONG THE PATH OF THE STORM..
RISK ASSESSMENT INTEGRATES RESEARCH AND SCIENTIFIC KNOWLEDGE GAINED FROM
“DISASTER LABORATORIES,” WITH EMERGING TECHNOLOGIES
INTO POLICY USING THE COMMUNITY’S POLITICAL
PROCESS.
PUBLIC POLICIES INTEGRATE TECHNICAL AND POLITICAL
SOLUTIONS FOR THE LONG-TERM BENEFIT AND HEALTH-CARE NEEDS OF PEOPLE, AND PROTECTION OF PROPERTY, INFRASTRUCTURE,
GOVERNMENT, AND ENTERPRISE IN THE COMMUNITY
COMMUNITYCOMMUNITY
DATA BASES DATA BASES AND INFORMATIONAND INFORMATION
•SEVERE WINDSTORMS•INVENTORY•VULNERABILITY•LOCATION
RISK ASSESSMENTRISK ASSESSMENT
RISK
ACCEPTABLE RISK
UNACCEPTABLE RISK
SEVERE WINDSTORM SEVERE WINDSTORM RISK REDUCTIONRISK REDUCTION
•PREVENTION/MITIGATION•PREPAREDNESS•EMERGENCY RESPONSE•RECOVERY and RECONSTRUCTION• EDUCATIONAL SURGES
POLICY OPTIONSPOLICY OPTIONS
Wind profileWind profile
Storm Hazards:Storm Hazards:-Wind pressure-Surge-Rain-Flood-Waves-Salt water-Missiles-Tornadoes
OceanOcean
Gradient WindGradient Wind