1. TORNADO OUTBREAK IN OKLAHOMA, ARKANSAS, AND IOWA Round One: April 26-27, 2014 Walter Hays, Global Alliance for Disaster Reduction, Vienna, Virginia, USA

2. The most destructive tornado outbreak of 2014 killed at least 18 people in three states and hammered the suburbs of Little Rock, Arkansas over a 200-mile-long path.

3. THE FORECAST: APRIL 14

4. ACTUAL: APRIL 26-27

5. In all, at least 31 tornadoes were recorded. They formed late in the day, and were especially destructive in Arkansas because they struck as night fell.

6. Some of the tornadoes were rated as EF-3, which have wind fields of at least 246 kph (136 mph).

7. VILONIA, ARKANSAS (ALSO HIT BY TORNADOES IN 2011)

8. IMPACTS Faulkner County, Ark., particularly the suburbs of Mayflower and Vilonia, was the hardest hit on Sunday, with as many as 18 people dead, including two children At least 150 homes destroyed. Two highways closed; 20,000 power outages

9. “ROUND TWO” MONDAY, APRIL 28 Millions of people braced for more severe weather as at least three tornadoes struck Mississippi on Monday afternoon.

10. TUEPLO, MISSISSIPPI: APRIL 28

11. INITIAL IMPACT REPORTS A tornado hit Tupelo and tracked northward, causing "significant property damage, but no deaths" Tueplo Mayor Jason Shelton said.

12. BACKGROUND SEVERE WINDSTORMS-- TORNADOES

13. UNDERSTANDING AND PREPARING FOR TORNADOES A PRIMER OF KNOWLEDGE THAT CAN MULTIPLY AND SPILL OVER FOR THE BENEFIT OF MILLIONS

14. THE PHYSICS OF SEVERE WINDSTORMS SEVERE WINDSTORMS: TORNADOES

15. COMMUNITYCOMMUNITY DATA BASES AND INFORMATION SEVERE WINDSTORM HAZARDS INVENTORY VULNERABILITY LOCATION RISK ASSESSMENT RISK ACCEPTABLE RISK UNACCEPTABLE RISK SEVERE WINDSTORM RISK REDUCTION PREVENTION/MITIGATION PREPAREDNESS EMERGENCY RESPONSE RECOVERY and RECONSTRUCTION EDUCATIONAL SURGES POLICY OPTIONS Wind profile Storm Hazards: -Wind pressure -Surge -Rain -Flood -Waves -Salt water -Missiles -TornadoesOceanOcean Gradient Wind

16. WIND AND WATER PENETRATE BUILDING ENVELOPE SEVERE WINDSTORMS SEVERE WINDSTORMS UPLIFT OF ROOF SYSTEM FLYING DEBRIS PENETRATES WINDOWS HEAVY PRECIPITATION IRREGULARITIES IN ELEVATION AND PLAN POOR WORKMANSHIP IGNORING NON-STRUCTURAL ELEMENTS CAUSES OF RISK CASE HISTORIES

17. BASIC PRINCIPLES OF PHYSICS UNDERPINNING WINDSTORMS HEAT AND HEAT FLOW PRESSURE AND PRESSURE FLOW GRAVITY FIELD KINETIC ENERGY POTENTIAL ENERGY

18. SEVERE WINDSTORMS TORNADOES OCCUR OVER LAND AS THE RESULT OF COLLISIONS OF COLD AND WARM AIR MASSES

20. 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.

21. 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.

22. MAP OF TORNADO ALLEY

23. 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.

24. 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.

25. PHYSICS OF A TORNADO

26. 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

27. HISTORIC OCCURRENCES

28. THIRTY TO FORTY TORNADOES STRIKE FIVE SOUTHERN STATES Mississippi, Alabama, Arkansas, Kentucky, and Tennessee impacted 54 dead FEBRUARY 5, 2008

29. LOCATION MAP

30. 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.

31. WARNING The people had ample warning to get out of harm’s way and take cover, … In spite of the fact that some of the warning sirens did not work.

32. A TORNADO TOUCHES DOWN NEAR ATKINS, ARKANSAS

33. DEVASTATION NEAR ATKINS, ARKANSAS

36. COLLAPSE OF WAREHOUSE IN SOUTH HAVEN, MS

37. COLLAPSE OF WALL IN SHOPPING MALL: MEMPHIS, TN

38. A FIRE BROKE OUT IN A NATURAL GAS PUMPING STATION: HARTSVILLE, TN

39. SEVERE THUNDERSTORM SYSTEM SPAWNS TORNADOES IN TEXAS: APRIL 24, 2008

40. A SUPERCELL

41. THE FUNNEL

42. 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)

43. IMPACTS IN WEST AND NORTH TEXAS HEAVY RAIN FALL CAUSED POWER OUTAGES AND MINOR FLOODING BASEBALL-SIZED HAIL

44. WIND DAMAGE

45. TORNADOES STRIKE IOWA AND MINNESOTA Continuation of deadliest tornado season in a decade Accompanied by large hail May 25, 2008

47. HUGO, MINNESOTA: DEBRIS MARKS STORM'S PATH

48. PARKERSBURG, IOWA: DAMAGE

49. PARKERSBURG, IOWA: LOOKING FOR SURVIVORS

50. LESSONS LEARNED FROM TORNADOES RECOVERY USUALLY TAKES LONGER AND COSTS MORE THAN EXPECTED.

51. LESSONS LEARNED FROM TORNADOES EVACUATION IS NOT TO THE STREET; IT IS TO THE BASEMENT OR THE “SAFE ROOM” BECAUSE THE WARNING IS EITHER VERY SHORT OR NON-EXISTANT.

52. LESSONS LEARNED FROM TORNADOES TIMELY COMMUN- ICATION OF CRITICAL INFORM- ATION IN THE FORM OF WATCHES AND WARNINGS IS ESSENTIAL FOR SAFETY.

53. LESSONS LEARNED FROM ALL TORNADOES HIGH VELOCITY WIND LIFTS THE ROOFS OFF OF BUILDINGS AND IS A KILLER IN TORNADOES.

54. LESSONS LEARNED FROM ALL SEVERE WINDSTORMS HIGH VELOCITY WIND AND PRESSURE CHANGES CAUSE BUILDINGS WITH INADEQUATE ENGINEERING DESIGN TO COLLAPSE.

55. RISK ASSESSMENT INTEGRATES RESEARCH AND SCIENTIFIC KNOWLEDGE GAINED FROM “DISASTER LABORATORIES,” WITH EMERGING TECHNOLOGIES INTO POLICY TO BE IMPLEMENTED IN THE COMMUNITY’S POLITICAL PROCESS.

56. PUBLIC POLICIES INTEGRATE TECHNICAL AND POLITICAL SOLUTIONS FOR THE LONG-TERM BENEFIT OF THE PEOPLE.