1. American Red Cross April 26, 2006 Michael Wyllie National Weather Service

2. What is a hurricane? A hurricane is a tropical cyclone. A cyclone is the general term for all circulating low pressure systems over tropical waters. In the Northern Hemisphere, cyclones circulate counterclockwise. Katrina 2005

3. Hurricane Source Regions

4. Tropical Cyclone Probabilities

6. Atlantic Hurricane Season June 1 – November 30

8. Early Hurricanes August 1635 – probably had major effects on Long Island. August 1635 – probably had major effects on Long Island. September 1815 – “The Great September Gale of 1815” – severe damage to south shore September 1815 – “The Great September Gale of 1815” – severe damage to south shore September 1821 – Crossed Long Island around Jamaica Bay – 21 lives lost. September 1821 – Crossed Long Island around Jamaica Bay – 21 lives lost.

9. High Seas The Long Island Express, 1938 High Seas The Long Island Express, 1938

10. 1938 Storm

11. Coastal Flooding Hurricane Carol, 1954 Coastal Flooding Hurricane Carol, 1954

13. Hurricane Donna The eye apparently was enlarged to almost 100 miles in width as it approached the New York coast. Several stations on Long Island reported sustained winds over 100 mph, and gusts of 125-30 mph were recorded at the eastern end of the island

14. Hurricane Belle – August 8-10, 1976

19. Fiercest Part of a Hurricane The fiercest and most dangerous part of a hurricane is located in the 50 to 75 miles wide region surrounding the eye of the hurricane.

20. Hurricane Hazards High Winds High Winds Tornadoes Tornadoes Storm Surge Storm Surge Flooding Rains Flooding Rains Rip Currents, High Surf, Rip Currents, High Surf, High Seas, and Battering Waves

21. 100% GREATER AT 350 FEET 70% GREATER AT 200 FEET 50% GREATER AT 140 FEET High-Rise Buildings at The Battery Impact of Hurricane Wind Pressures at Various Altitudes Source: “Minimum Design Loads for Buildings and Other Structures” ASCE 7-88, July 1990

22. 100% GREATER AT 350 FEET 70% GREATER AT 200 FEET 50% GREATER AT 140 FEET George Washington Bridge Impact of Hurricane Wind Pressures at Various Altitudes Source: “Minimum Design Loads for Buildings and Other Structures” ASCE 7-88, July 1990 Center Span Elevation of 213.0 feet (NGVD)

23. Goethals Bridge 140.0 feet Bayonne Bridge 150.0 feet Outerbridge Crossing 145.0 feet Triborough Bridge 145.6 feet Bronx-Whitestone Bridge 138.6 feet Throgs Neck Bridge 145.6 feet Henry Hudson Parkway Bridge 145.6 feet Marine Parkway Bridge 57.0 feet Verrazano-Narrows Bridge 230.6 feet Williamsburg Bridge 133.0 feet Manhattan Bridge 135.0 feet Queensborough Bridge 135.0 feet Center Span Elevations of Various New York City Bridges

24. HIGH LEVEL BRIDGE CLOSURES Storm Forward Speed Hours Before Tropical Storm Winds Occur at the Surface (Completion of Evacuation) 20mph 2 to 3 Hours 40mph 1 to 2 Hours 60mph 1 Hour or Less

25. The Wind effect on the Trees Last sustained winds over 60 mph was in Hurricane Gloria in 1985 – 21 years ago, Bob in 1991 only affected eastern Long Island. Last sustained winds over 60 mph was in Hurricane Gloria in 1985 – 21 years ago, Bob in 1991 only affected eastern Long Island. Isolated severe thunderstorms have thinned out dead trees in only a few areas. Much of the stands of trees over NYC and Long Island have not been stressed and will come down quickly. Isolated severe thunderstorms have thinned out dead trees in only a few areas. Much of the stands of trees over NYC and Long Island have not been stressed and will come down quickly. With sustained winds of 80+ mph and gusts at or above 100 mph, Gloria would look like a walk in the park. With sustained winds of 80+ mph and gusts at or above 100 mph, Gloria would look like a walk in the park.

26. TORNADOES Nearly 60% of the hurricanes that made landfall between 1948 & 2004 spawned at least one tornado. In 2004 the storms set records! In 2005 Hurricane Rita moved into 6 th place with the number of tornadoes it spawned! Nearly 60% of the hurricanes that made landfall between 1948 & 2004 spawned at least one tornado. In 2004 the storms set records! In 2005 Hurricane Rita moved into 6 th place with the number of tornadoes it spawned! Most of these occurred in the right front quadrant of the storm. Most of these occurred in the right front quadrant of the storm.

28. Storm Surge It is the abnormal rise in water caused by the wind and pressure forces of a hurricane. It is the abnormal rise in water caused by the wind and pressure forces of a hurricane. Through history this has been the greatest hazard from the hurricane and has been the greatest cause of fatalities, although this is changing. Through history this has been the greatest hazard from the hurricane and has been the greatest cause of fatalities, although this is changing.

30. Shelf Slopes Storm Surge Shallow shelves result in higher surges and lower waves: New York City Shallow shelves result in higher surges and lower waves: New York City Steep shelf's result in lower surges and higher waves: Eastern Long Island Steep shelf's result in lower surges and higher waves: Eastern Long Island Gentle Shelf InclineSteep Shelf Incline

31. SLOSH does not incorporate the effects of: Rainfall amounts. Rainfall amounts. River flow. River flow. Wind driven waves. Wind driven waves. Heights of astronomical tides. Heights of astronomical tides.

32. Hurricane Angle of Approach

33. 6.6 6.49.1 9.3 7.8 9.0 10.4 10.0 10.3 10.5 10.1 7.5 8.2 7.9 6.3 6.5 6.16.2 Storm Surge Elevations (in feet) ~ Category 1

34. 15.6 11.214.0 15.2 15.1 14.8 15.7 16.0 15.7 16.6 15.8 17.2 15.0 11.7 11.5 11.3 13.015.7 Storm Surge Elevations (in feet) ~ Category 2

35. Jamaica Bay Belt Parkway Howard Beach Rockaway Boulevard Rosedale Cross Bay Boulevard Aqueduct Raceway

36. Jamaica Bay Belt Parkway Howard Beach Rockaway Boulevard Rosedale Cross Bay Boulevard Aqueduct Raceway

37. 24.5 15.720.4 20.9 21.0 20.0 22.3 22.0 22.8 23.9 22.4 20.5 17.7 14.9 17.3 16.6 14.825.0 Storm Surge Elevations (in feet) ~ Category 3

38. 31.2 20.826.6 27.0 27.4 25.2 27.6 26.7 28.0 28.7 25.6 30.8 28.1 18.1 22.2 24.631.3 Storm Surge Elevations (in feet) ~ Category 4

39. New York City Slosh Values

40. Flooding Rains Flooding Rains Excessive Rainfall is likely when tropical systems make landfall. Excessive Rainfall is likely when tropical systems make landfall. The forward speed of the storm plays a big role in the amount of precipitation that falls. The forward speed of the storm plays a big role in the amount of precipitation that falls. Examples: Agnes in 1972, Floyd in 1999, Ivan and Jeanne in 2004. Examples: Agnes in 1972, Floyd in 1999, Ivan and Jeanne in 2004.

42. Flagler Beach, Florida FLAGLER BEACH, FLORIDA HIGH SURF WEAK SIDE - CAT 3

43. Battering Waves Hurricane Carol, 1954 Battering Waves Hurricane Carol, 1954

44. What About the Beaches? We have had three severe winters followed by a relatively mild one in the Northeast. We have had three severe winters followed by a relatively mild one in the Northeast. Many of our dune structures are badly diminished or totally gone compared to what protected us in 1985 when Gloria hit. Many of our dune structures are badly diminished or totally gone compared to what protected us in 1985 when Gloria hit. Some communities have replenished the beaches on their own. Some communities have replenished the beaches on their own. Some have received natural replenishment. In other areas there is no beach left at all. Some have received natural replenishment. In other areas there is no beach left at all. Much of the missing dunes and beaches are a result of the disastrous nor’easters during the 1990’s as well as last three winters…we still haven’t recovered. Much of the missing dunes and beaches are a result of the disastrous nor’easters during the 1990’s as well as last three winters…we still haven’t recovered.

45. Necessary Ingredients for Hurricanes Warm Tropical Water Warm Tropical Water Sea surface temps above 27 degrees Celsius/80 degrees Fahrenheit Sea surface temps above 27 degrees Celsius/80 degrees Fahrenheit Tropical Wave Tropical Wave Seedling storms move off the coast of Africa Seedling storms move off the coast of Africa High Pressure Aloft High Pressure Aloft Upper atmosphere high Upper atmosphere high Easterly or Weak Westerly Upper Level Flow Easterly or Weak Westerly Upper Level Flow

46. REWIND… The hurricane season of 2005! REWIND… The hurricane season of 2005!

47. One for the record books! 27(8) named storms! One for the record books! 27(8) named storms!

48. Why did we have so many storms?

49. The hurricane’s energy source – warm ocean sea surface temperatures -- were above average!

51. Weak El Nino or neutral conditions occurred during all of the 2005 hurricane season. Weak El Nino or neutral conditions meant weak vertical shear over the tropical Atlantic. This resulted in conditions favorable for development and strengthening.

53. What Happened? 27(28) Named Storms (Zeta) – RECORD 27(28) Named Storms (Zeta) – RECORD -There was actually another storm! -There was actually another storm! 10 is Normal 15 Hurricanes 15 Hurricanes 6 is Normal 5 Retired Hurricane Names 5 Retired Hurricane Names Dennis, Katrina, Rita, Stan, and Wilma

54. The 2005 Hurricane Season

55. But the number of storms is not the only issue…it also counts on where the storms hit!

56. On average, 1 out of every 3 major hurricanes that develops hits the United States. Between 1995 and 2003, thirty-two major hurricanes formed,......but only 3 major hurricanes - - Opal (1995), Fran (1996), and Bret (1999) - - made landfall during that time!

57. In 2004, the “Law of Averages” began to catch up with us as 3 out of the 6 major hurricanes made landfall. In 2005, 5 out of 7 of the major hurricanes made landfall. Let’s hope this trend doesn’t continue!

58. Tracks of Major Hurricanes Making Landfall on the U.S. East Coast INACTIVE PERIOD INACTIVE PERIOD ACTIVE PERIOD ACTIVE PERIOD

59. If Global Warming affects sea surface temperatures can it therefore affect hurricanes???

60. Mean Decadal Temperatures for Central Park 1870-2005

61. Therefore, you would think that global warming would cause more hurricanes…RIGHT! But…wait just a minute!

62. What else is coming into play here? THE MULTIDECADAL CYCLE!!!!!

63. ACTIVE INACTIVE ACTIVE INACTIVE ? ?

64. A dilemma in the science of hurricanes today…is it Global Warming or the Multidecadal Cycle??? The meteorology community is stymied!!!! One thing for sure…we must be prepared for more and stronger hurricanes for the next several years!

66. Not to sound the alarm too soon but we are also in a weak La Nina situation in the Pacific. This means that we expect WEAK SHEAR over the tropical Atlantic Basin at least through the beginning of the Hurricane Season. Dr. William Gray and his Hurricane Forecasters from Colorado State are forecasting 17 named storms, 9 hurricanes and 4 majors storms this year!