Severe Thunderstorms are generated by atmospheric imbalance and turbulence due to the combination of the following conditions: unstable warm air rising rapidly into the atmosphere; sufficient moisture to form clouds and rain; and upward lift of air currents caused by colliding cold and warm weather fronts, sea breezes, or mountains.

Severe Thunderstorms bring high wind, lightning, and hail, and often result in flooding from heavy rains and damages from tornadoes. Most severe thunderstorms and resulting lightning, hail, and tornado events occur during the summer months, and at a lesser intensity, during the spring and fall.

Thunder is the sound made by a flash of lightning. It can be heard up to 10 miles away from the lightning strike. If you can hear thunder when you’re outside, you can potentially be struck by lightning!

• The sound of thunder travels about 1 mile every 5 seconds. If you count the seconds between the flash of lightning and the crack of thunder and divide the number of seconds by 5, you get the number of miles away lightning is.

• If you hear thunder less than 30 seconds after the flash, seek shelter and remain there for at least 30 minutes after you hear the last thunder roll.
  
  

Lighting is a rapid discharge (like a giant spark!) of electricity in the atmosphere, or between the atmosphere and the ground.

• It is one of the top weather killers in the U.S. Lightning injures many more people than it kills, and leaves some victims with life-long health problems.
• Most lightning fatalities and injuries occur when people are caught outdoors in the summer months during the afternoon and evening.

Lightning is generated by the buildup of charged ions in a thundercloud, and the discharge of a lightning bolt interacts with the best conducting object or surface on the ground.  The air channel of a lightning strike reaches temperatures higher than 50,000 degrees Fahrenheit.  The rapid heating and cooling of the air near the channel causes a shock wave, which produces thunder.

Lightning can result in electrocution; vaporization of materials along the path of the strike; fire caused by the strike, and sudden power surges that can damage electrical and electronic equipment. 

Millions of dollars of damages result from lightning strikes.  While property damage is the major hazard associated with lightning, it should be noted that lightning strikes kill nearly 100 people each year in the United States.

Hail consists of balls or lumps of ice ranging from very small to very large sizes. Severe weather warnings are issued for hail when the hailstones reach sizes that can cause severe damages to humans, buildings, and crops.

• The largest recorded hailstones measured 8 inches in diameter and weighed about 2 pounds!

The size of hailstones is a direct function of the severity and size of the storm.  Small hail is unlikely to cause personal injury or serious property damage, except to crops. On the other hand, larger hailstones can total cars, ruin roofs, break windows, damage shutters, kill animals, and seriously injure people.

Tips to Stay Safe!

When you hear thunder, you can potentially be struck by lightning! There are NO SAFE PLACES OUTDOORS during a storm. Immediately move to a safe shelter such as a building or enclosed metal-topped vehicle with the windows up. As a storm is approaching, here are things you can do to stay safe:

• Go inside and stay away from windows.
• Never shelter under a tree.
• Bring pets inside.
• Stay indoors.
• Don’t leave toys (bikes), loose items outside. They can cause damage if airborne.

Visit these websites for more information about severe weather and steps to take to keep your family safe:

Lightning

National Weather Service (http://www.lightningsafety.noaa.gov/)

Ready.gov (http://www.ready.gov/thunderstorms-lightning)

Severe Thunderstorms

Ready.gov (http://www.ready.gov/severe-weather)

American Red Cross (http://www.redcross.org/prepare/disaster/thunderstorm)