Lightning Warning Signs You Shouldn't Ignore

Know When You're at High Risk From a Lightning Strike!

hikers standing in thunderstorm
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Nothing ruins a summer cookout, dip in the pool, or camping trip like a thunderstorm.

If you are outdoors when a thunderstorm rolls up, it can be tempting to want to stall as long as possible before going indoors. But how do you know when it's time to stop what you're doing and head inside? Keep a lookout for these signs; they'll warn you when it's time to seek shelter indoors and when lightning may be about to strike you.

The Threat of Lightning Exists at All Times During a Thunderstorm

Lightning always occurs with thunderstorms, but it isn't necessary for a storm to be directly overhead for you to be in danger of a lightning strike. The threat of lightning actually starts as a thunderstorm approaches, peaks when the storm is overhead, and then gradually diminishes as the storm moves away.

Cloud-to-Ground Lightning Is Near If...

If you notice one or more of these early signs of an approaching storm, you should seek shelter immediately to reduce your risk of lightning injury or death.

  • A rapidly growing cumulonimbus cloud. Although cumulonimbus clouds appear bright white and form in sunny skies, don't be fooled—they're the beginning stage of a developing thunderstorm! If you notice them growing taller and taller up in the sky, you can rest assured a storm is in-the-making and soon headed your way.
  • Increasing winds and a darkening sky. These are telltale signs of an approaching storm.
  • Audible thunder. Thunder is the sound created by lightning, so if thunder can be heard, lightning is near. You can determine how near (in miles) by counting the number of seconds between thunderclaps and dividing that number by 5.
  • A severe thunderstorm warning. The National Weather Service issues a severe thunderstorm warning when severe storms have been detected on weather radar, or confirmed by storm spotters. Cloud-to-ground lightning is often a main threat of such storms.

    Seek Shelter Here, and Fast!

    The best places to seek shelter from lightning are:

    • Enclosed buildings/structures, and
    • Vehicles with all windows rolled up.

    How Your Body Warns of A Lightning Strike

    When lightning makes a close or direct strike to you, you might experience one or more of these warning signs a few seconds beforehand:

    • Your hair standing up on end
    • Tingling skin
    • A metallic taste in your mouth
    • The smell of chlorine/swimming pool (This is ozone, which is produced when nitrogen oxides from lightning interact with other chemicals and sunlight.)
    • Sweaty palms
    • A vibrating, buzzing, or crackling sound coming from metal objects around you.

    If any of these happen, there may be nothing you can do to avoid being struck and possibly injured or killed. However, if you find you do have a moment to react, you should run as fast as you can to a safer location. Running limits the time both of your feet are on the ground at any one time, which reduces the threat from ground current (That is, lightning that travels outward from the strike point along the ground surface).

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