Presentation on theme: "Thunderstorms, Hurricanes and Tornadoes. Thunderstorm Facts Right now there are about 2,000 thunderstorms occurring worldwide There are about 45,000 thunderstorms."— Presentation transcript:
When to expect Hurricane season is June through November Peak is in September
Formation of Hurricanes Tropical Depression Tropical Storm Hurricane
Tropical Depression Cluster of organized thunderstorms Not very compact Sustained winds of at least 30 mph Given a number
Tropical Storm Winds above 39 mph Given a name More organized If hits land, most damage caused is by rainfall.
Hurricane Winds over 74 mph Well defined center of circulation Eye Wall Damage from includes: –Wind –Storm surge –Rain
Pressure in hurricane A way to tell strength of hurricane is by its pressure Measured in millibars (mb) Higher pressures are weak, lower are stronger
Naming System A list of names from A-W (excluding Q) Alternate from male to female 6 lists, repeated in cycle Big name storms replaced
Saffir-Simpson Scale Designed by Herbert Saffir and Bob Simpson Divides hurricanes into categories based on maximum sustained winds.
Category 1 Winds- 74-95 mph Storm Surge- 4-5 ft. Pressure- 986mb Damage- mobile homes, trees, minor costal flooding
Category 2 Winds- 96-110 mph Storm surge- 6-8 ft. Pressure- 965- 979 mb Damage- Some roof and window. Damage to piers on coast. Small crafts. vegetation
Category 3 Winds- 111-130 mph Storm surge- 9-12 ft. Pressure- 945-964 mb Damage- structure damage to homes and buildings. Mobile homes destroying. Major coastal flooding with a potential for inland flooding.
Category 4 Winds 131-155 mph Storm surge- 13-18 ft. Pressure- 920-944 mb Damage- Complete roof damage. Major erosion to beaches. Further inland flooding.
Category 5 Winds- Greater than 156 mph Storm surge- over 19 ft. Pressure- less than 920 mb Damage- Roofs torn off, buildings collapse, major inland flooding.
Hurricane Watch A hurricane poses a possible threat within the next 36 hours
Hurricane Warning Hurricane conditions expected within 24 hours