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Emergency Guide Thunderstorm and Lightning

Thunderstorms and Lightning

All thunderstorms produce lightning and are dangerous. Other hazards associated with thunderstorms include tornadoes, strong winds, hail, and flash flooding.

Facts About Thunderstorms

  • They may occur singly, in clusters, or in lines
  • Some of the most severe occur when a single thunderstorm affects one location for an extended period of time
  • Thunderstorms typically produce heavy rain for a brief period of 30 minutes to an hour
  • Warm, humid conditions are highly favorable for thunderstorm development
  • Approximately 10% of thunderstorms are classified as "severe" one that produces hail at least three-quarters of an inch in diameter, has winds of 58 miles per hour or higher, or produces a tornado

Facts about Lightning

  • Lightning's unpredictability increases the risk to individuals and property
  • Lightning often strikes outside of heavy rain and may occur as far as 10 miles from any rainfall
  • "Heat lightning" is actually lightning from a thunderstorm too far away to be heard
  • Most deaths from lightning occur when people are caught outdoors in the summer months during the afternoon or evening
  • The chances of a person being struck by lightning are estimated at 1 in 3,000
  • Lightning strike victims carry no electrical charge and should be helped immediately

Severe Thunderstorm Watch

The National Weather Service issues a severe thunderstorm watch when severe thunderstorms are likely to occur.

Severe Thunderstorm Warning

A warning indicates imminent danger to life and property of those in the path of the storm.

During a Thunderstorm

  • Get inside a home, building, or hardtop vehicle. Although injuries may occur if a vehicle is struck, a person is much safer inside the vehicle than outside it.
  • Avoid showering or bathing as metal bathroom plumbing and fixtures can conduct electricity causing shock or electrocution
  • Use a corded phone only for emergencies - cordless and cellular telephones are safe to use
  • Unplug appliances and other electrical items such as computers, stereos, televisions and air conditioners - power surges can cause serious damage
  • Use a battery-operated radio for weather updates

If outdoors:

  • Avoid objects that can act as a lightning rod including trees
  • Seek shelter in a low lying area such as a ravine or valley
  • Be alert to the possibility of flash floods
  • If on open water, get to shore and find shelter immediately
  • Remember that when hair stands on end (anywhere on the body) it is an indication that lightning is about to strike - when this happens, squat down minimizing contact with the ground
  • Do not lie flat on the ground

Additional information is available on the following website:

National Oceanographic and Atmospheric Administration