Thunderstorms are relatively small when compared to hurricanes, but despite their size, they are dangerous. At any given moment, 1,800 thunderstorms are occurring around the world. Thunderstorms produce many hazards, such as tornadoes, lightning, strong winds, flash flooding and hail.
Straight-line winds can exceed 100 mph and account for most of the damage we see from thunderstorms. Downbursts and microbursts can cause damage equivalent to a strong tornado. These winds rapidly descend beneath the thunderstorm. There is little or no rain associated with a microburst.
Lightning is another dangerous component of thunderstorms that causes an average of 80 deaths and 300 injuries every year. In addition, annual lightning strikes account for about 10,000 forest fires annually.
Hail causes more than $1 billion in damage to property and crops every year. Large hailstones can fall at speeds in excess of 100 mph.
A severe thunderstorm watch means conditions are favorable for the development of severe thunderstorms. Remain alert for further updates.
A severe thunderstorm warning means evere thunderstorms are in the area. Take cover indoors immediately. Listen to the local television or radio station for further weather updates.
To determine how far away a thunderstorm is, count the number of seconds between the lightning flash and the next clap of thunder. Divide that number by five to determine the number of miles away it is from you. Go indoors if, after seeing lightning you cannot count to 30 before hearing the thunder clap. Stay inside for at least 30 minutes after the last thunder clap you hear.
Before the storm
- Develop your disaster plan and disaster kit.
- Make sure your NOAA weather or all-hazards radio is working properly and has fresh batteries.
- Familiarize yourself with the severe weather alerts.
- Practice your plan – have frequent drills.
- Identify a safe place to take shelter or, better yet, build a safe room.
- Check for hazards in the yard. Keep your trees trimmed. Cut down dead trees, which can break off during storms and cause injuries to people and pets and can damage homes or other property.
- Keep a highway map handy so you can track a storm's path from weather bulletins.
- Check the weather forecast before leaving for extended outdoor activities. Remain alert for signs of developing storms. Postpone outdoor activities if thunderstorms are imminent.
- When severe weather threatens, check on the elderly, the very young and the disabled.
During the storm
- Seek shelter inside if possible. Move to a sturdy building. Do not take shelter in small sheds, under trees or in convertible automobiles.
- If lightning is occurring and sturdy shelter is not available, go to a hardtop vehicle, keep the windows up, and do not touch anything metal.
- If there is no shelter available, find a low spot away from trees, fences or poles. Make sure your spot will not be subject to flooding.
- If you cannot avoid trees, take shelter under the shorter trees.
- If you feel your skin tingle or your hair stand on end, squat low to the ground on the balls of your feet. Put your hands over your ears and your head between your knees. Make yourself as small of a target as possible. Do not lie down. You need as little contact with the ground as possible.
- If you are swimming of fishing in a boat, get to land and find shelter immediately.
- Do not take a shower or a bath while it is storming.
- Stay off the telephone.
- Turn off the air-conditioner as power surges can cause serious damage.
- Go to your shelter. If at home, take your disaster kit with you.
- Listen to the weather updates on your radio.
- Remain in your shelter until the warning is over.
After the storm
- Make sure everyone is all right. Give first aid if you have been trained. Be alert to downed power lines and avoid them. Report them to the utility company.
- Check on friends and family, especially the very young, the very old and the disabled.
- If there has been damage to your home or business, contact your insurance agent.
- Avoid driving unless necessary. Just because your street is clear of debris does not mean other streets were not harder hit.
- If you must drive, be wary of washed out roads and flash flooding. Turn around; don’t drown!