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Thunderstorms & Lightning

All thunderstorms produce lightening 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 thunderstorms 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 victims carry no electrical charge and should be helped immediately

Severe Thunderstorm Watch

A Severe Thunderstorm Watch is issued when conditions are favorable for the development of severe thunderstorms. A severe thunderstorm is a thunderstorm that produces 3/4 inch hail or larger in diameter and/or winds equal or exceed 58 miles an hour. Watches are usually issued for a duration of 4 to 8 hours, and are normally issued well in advance of the actual occurrence of severe weather. During the watch, people should review severe thunderstorm safety rules and be prepared to move a place of safety if threatening weather approaches.

Severe Thunderstorm Warning

A Severe Thunderstorm Warming is issued when either a severe thunderstorm is indicated by radar or a spotter reports a thunderstorm producing hail 3/4 inch or larger in diameter and/or winds equal or exceed 58 miles an hour. People in the affected area should seek safe shelter immediately. Severe thunderstorms can produce tornadoes with little or no advance warning. Lightning frequency is not a criteria for issuing a severe thunderstorm warning. They are usually issued for a duration of one hour. They can be issued without a Severe Thunderstorm Watch being already in effect.

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
  • Cordless and cellular phones are safe to use - on the other hand, use a corded phone only for emergencies
  • 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
  • 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 while minimizing contact with the ground
  • Do not lie flat on the ground