Fire-Rescue - Domestic Preparedness and Emergency Management Bureau - Thunderstorms and Lightning
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Thunderstorms and Lightning

Thunderstorms – ALL Thunderstorms are dangerous! The typical thunderstorm is 15 miles in diameter and lasts an average of 30 minutes. Of the estimated 100,000 thunderstorms that occur each year in the United States, about 10 percent are classified as severe. A thunderstorm, which produces tornadoes, hail 0.75 inches or more in diameter, or winds of 58 mph or more is considered to be severe. Structural wind damage to property as a result of the storm may also imply the occurrence of a severe thunderstorm.

To determine how far away a thunderstorm may be:

  • Count the number of seconds between a flash of lightning and the next clap of thunder.
  • Divide this number by 5 to determine the distance to the lightning in miles.
  • Remember – if you can hear thunder, you are close enough to be struck by lightning.

Severe Thunderstorm Watch - An statement issued by the National weather Service (NWS) that indicates thunderstorms are possible in your area, i.e., that conditions are more favorable than usual for its occurrence. It is recommended that you plan, prepare, and increase your thunderstorm awareness (i.e., be alert for changing weather and approaching storms). Know what other cities or counties are in the watch area by listening to NOAA Weather Radio or your local radio/television stations. Watch the sky, think about what to do if a thunderstorm materializes.

Severe Thunderstorm Warning - A statement issued by the NWS local offices indicating that a thunderstorm is either imminent, has been reported by spotters or indicated by weather radar. A warning indicates imminent danger to life and property to those in the path of the storm, and that there is a need to take action to protect life and property.

Lightning – Florida is considered to be the lighting capital of the United States. The average lightning bolt is only one inch in diameter but can carry as much as 100 million volts and pack heat to 50,000 degrees Fahrenheit, (or three times hotter than the surface of the sun). Lightning can strike more than once in the same place and can strike up to 25 miles from a parent storm. It can literally strike “out of the blue.”

  • If outside, follow the 30/30 rule: if the time between seeing the flash of lightning and hearing the thunder is less than 30 seconds, take shelter; you are in a strike zone.
  • Immediately get away from pools, lakes and other bodies of water.
  • Get off the beach.
  • Never use a tree as a shelter.
  • Avoid standing near tall objects.