Emergency Management

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 U.S., about 10 percent are classified as severe.

A thunderstorm that either produces tornadoes, hail over 3/4 inch 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 estimate of how far away a thunderstorm is:

  • 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.

If you can hear thunder, you are close enough to be struck by lightning.

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

Click here to see current watch information.

Download the Thunderstorms, Tornadoes and Lightning Guide created by the National Oceanic and Atmospheric Administration (NOAA)

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