THERE ARE 4 MAIN HAZARDS associated with severe thunderstorms:
* WHAT IS A THUNDERSTORM?: By its simplest definition, a thunderstorm is a rain shower that is accompanied with lightning and thunder.
* HOW OFTEN DOES FSU GET THUNDERSTORMS? The FSU Main Campus in Tallahassee averages 80 days of thunderstorms per year, primarily during the summer months of June, July, and August when thunderstorms are almost a daily occurrence. Thunderstorms also occur in the spring and fall in association with passage of weather fronts.
* HOW CAN A THUNDERSTORM BE DANGEROUS? First and foremost, the biggest threat from any thunderstorm is lightning. However, another common characteristic of a thunderstorm is torrential downpours that can obscure visibility, especially when driving at fast speeds, and result in flooding.
* WHEN IS A THUNDERSTORM CONSIDERED 'SEVERE'? By National Weather Service definition, a thunderstorm is considered "severe" when one or more of the following conditions exists:
- Winds or wind gusts in excess of 58mph.
- Hail greater than 3/4" in diameter.
- Potential for tornado development.
* HOW OFTEN DOES FSU GET SEVERE THUNDERSTORMS? The FSU Main Campus in Tallahassee averages 15 severe thunderstorm warnings per year.
* WHAT KIND OF DAMAGE CAN THUNDERSTORM WINDS DO? Winds of 58mph to 85mph associated with most severe thunderstorms can peel shingles off some roofs; damage gutters, siding or other lightweight structures like carports and sheds; break tree branches; and push over shallow-rooted trees. Falling trees and branches often cut utility lines.
Extremely isolated microbursts of straight-lined winds can occassionally exceed 85mph, up to 110mph, which can severely strip roofs; overturn or destroy mobile homes; break doors and windows; and topple numerous trees.
* WHAT ARE SOME RECENT EXAMPLES OF THUNDERSTORM WIND DAMAGE? On April 2, 2009, a stright-line thunderstorm wind gust of about 75mph toppled close to two hundred trees at the Seminole Golf Course and Alumni Village, causing over $250,000 in damage.
On July 2, 2009, an estimated 70 to 85-mph thunderstorm wind gust toppled trees and tore sections of roof off of the Alltel store on South Monroe Street, Toys-R-Us store on Apalachee Parkway, and blew off some roof-top air conditioning units.
* WHAT KIND OF DAMAGE CAN HAIL DO? Hail 3/4" or greater is the size of a penny or greater. Surely, if these were to ping you in the head, it would hurt! They can also ding and dent vehicles, break windows, and damage roof shingles and tiles. Obviously, the bigger the hail stone, the greater the damage potential. Hailstones associated with Tallahassee area thunderstorms rarely exceed 1-inch, or about the size of a quarter.
Hail Size Comparisons Pea 0.25 inches Marble 0.5 inches Dime 0.6 inches Penny 0.75 inches Nickel 0.88 inches Quarter 1.0 inches Ping-pong ball 1.5 inches Golf Ball 1.7 inches Chicken Egg 2.0 inches Tennis Ball 2.5 inches Baseball 2.75 inches Grapefruit 4.0 inches Softball 4.5 inches
For More Information:
National Weather Service - Severe Storm Safety
Florida Division of Emergency Management - Thunderstorms
