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.