How should I prepare for a thunderstorm while outdoors?

  • Postpone activities immediately, and do not wait for rain to begin. Thunder and lightning can strike without rain.
  • Watch cloud patterns and conditions for signs of an approaching storm.
  • Designate safe locations and move or evacuate to a safe location at the first sound of thunder. Every 5 seconds between the flash of lightning and the sound of thunder equals 1 mile of distance.
  • Where possible, quickly find shelter in a substantial building (not a carport, open garage or covered patio), or in a fully enclosed metal vehicle, such as a hardtop car (not a convertible), truck, or van, with the windows completely shut.
  • Use the 30-30 rule where visibility is good and there is nothing obstructing your view of the thunderstorm. When you see lightning, count the time until you hear thunder.
    • If that time is 30 seconds or less, the thunderstorm is within 6 miles. Seek shelter immediately. The threat of lightning continues for a much longer period than most people realize. 
    • Wait at least 30 minutes after the last clap of thunder before leaving shelter. If inside during a storm, keep away from windows. Injuries may occur from flying debris or glass if a window breaks.
  • Stay away from plumbing, electrical equipment, and wiring during a thunderstorm.
  • Do not use a corded telephone or radio transmitter except for emergencies.
  • If there is a tornado alert, go to the basement of the lowest interior level of a building.


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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.