Thunderstorms are intense local storms averaging 20 miles across and reaching as high as 10 miles. They are caused by a combination of moisture, rapidly rising warm air, and a force capable of lifting air, such as the meeting of a warm and cold front, a sea breeze, or a mountain. Thunderstorms are always accompanied by lightning, which kills between 75 to100 Americans each year.
Thunderstorms can bring heavy rain (which can cause flash flooding) strong winds, hail, lightning, and tornadoes. They occur in all 50 states and all US territories.
Before Lightening Strikes
- Keep an eye on the sky. Look for darkening skies, flashes of light, or increasing wind. Listen for the sound of thunder.
- If you can hear thunder, you are close enough to the storm to be struck by lightning. Go to a safe shelter immediately.
- Listen to NOAA Weather Radio, commercial radio, or television for the latest weather forecasts.
When a Storm Approaches
- Find shelter in a building or car. Keep car windows closed and avoid convertibles.
- Telephone lines and metal pipes can conduct electricity. Unplug appliances. Avoid using the telephone or any electrical appliances.
- Avoid taking a bath or shower, or running water for any other purpose.
- Turn off the air conditioner. Power surges can overload the compressor, resulting in a costly repair job.
- Draw blinds and shades over windows. If windows break due to objects blown by the wind, the shades will prevent glass from shattering into your home.
If You Are Caught Outside
- If you are in the woods, take shelter under the shorter trees.
- If you are boating or swimming, go to land and find shelter immediately.
Protecting Yourself Outside
- Go to a low-lying place
- Avoid natural lightning rods such as tall, isolated trees in an open area or on top of a hill. Also avoid poles and metal objects such as wire fences, golf clubs, and metal tools.
- Make sure the place you pick is not at risk of flooding.
Be a Very Small Target
- Squat low to the ground. Place your hands on your knees with your head between them. Make yourself the smallest target possible.
- Do not lie flat on the ground - this will make you a larger target.
After the Storm Passes
- Stay away from storm-damaged areas.
- Listen to the radio for information and instructions.
If Someone Is Struck by Lightning
- People struck by lightning carry no electrical charge and can be handled safely.
- Call for help. Get someone to dial 911 or your local Emergency Medical Services (EMS) number.
- The injured person has received an electrical shock and may be burned, both where they were struck and where the electricity left their body. Check for burns in both places.
- Give first aid. If breathing has stopped, begin rescue breathing. If the heart has stopped beating, a trained person should give CPR.