The typical thunderstorm is 15 miles in diameter and lasts an average of 30 minutes. Despite their small size, ALL thunderstorms are dangerous! Of the estimated 100,000 thunderstorms
that occur each year in the United States, about 10 percent are classified as severe.
Straight-line winds
- Straight-line winds are any winds not associated with the rotation of a tornado. Straight-line winds are responsible for most thunderstorm wind damage.
- Straight-line winds can exceed 125 mph!
- A downburst is a small area of rapidly descending air beneath a thunderstorm.
- A downburst can cause damage equivalent to a strong tornado and can be extremely hazardous to aviation.
Hail
- Strong rising currents of air within a storm, called updrafts, carry water droplets to a height where they freeze. Ice particles grow, becoming too heavy to be supported by the updraft, and fall to the ground. Hail is larger than sleet, and forms only in thunderstorms.
- Large hailstones can fall at speeds faster than 100 mph!
- The largest hailstone ever recovered in the United States was a 7-inch-wide chunk of ice that landed in Aurora, Nebraska, in June 2003.
- An accurate weight could not be determined for the Aurora hailstone. A 1970 Coffeyville, Kansas, hailstone weighing 1.67 pounds with a 5.7-inch diameter remains the heaviest hailstone weighed and verified in the United States.
HOW TO STAY SAFE WHEN A THUNDERSTORM THREATENS
Prepare NOW
- Know your area’s risk for thunderstorms. In most places, they can occur year-round and at any hour.
- Sign up for your community’s warning system. The Emergency Alert System (EAS) and National Oceanic and Atmospheric Administration (NOAA) Weather Radio also provide emergency alerts.
- Identify nearby, sturdy buildings close to where you live, work, study, and play.
- Cut down or trim trees that may be in danger of falling on your home.
- Consider buying surge protectors, lightning rods, or a lightning protection system to protect your home, appliances, and electronic devices.
Survive DURING
- When thunder roars, go indoors. A sturdy building is the safest place to be during a thunderstorm.
- Pay attention to weather reports and warnings of thunderstorms. Be ready to change plans, if necessary, to be near shelter.
- When you receive a thunderstorm warning or hear thunder, go inside immediately.
- If indoors, avoid running water or using landline phones. Electricity can travel through plumbing and phone lines.
- Protect your property. Unplug appliances and other electric devices. Secure outside furniture.
- If boating or swimming, get to land and find a sturdy, grounded shelter or vehicle immediately.
- If necessary, take shelter in a car with a metal top and sides. Do not touch anything metal.
- Avoid flooded roadways. Turn Around. Don’t Drown! Just six inches of fast-moving water can knock you down, and one foot of moving water can sweep your vehicle away.
Be Safe AFTER
- Listen to authorities and weather forecasts for information on whether it is safe to go outside and instructions regarding potential flash flooding.
- Watch for fallen power lines and trees. Report them immediately.
Please visit the links below to learn more about thunderstorms and what you can do to protect your family.
Weather.gov
Fema.gov