Thunderstorms affect relatively small areas when compared to hurricanes and winter storms. The typical thunderstorm is 15 miles in diameter and lasts an average of 30 minutes. Nearly 1,800 thunderstorms are occurring at any moment around the world. That's 16 million a year!

Despite their small size, all thunderstorms are dangerous. Every thunderstorm produces lightning, which kills more people each year than tornadoes. Heavy rain from thunderstorms can lead to flash flooding. Strong winds, hail, and tornadoes are also dangers associated with some thunderstorms.

Of the estimated 100,000 thunderstorms that occur each year in the United States, only about 10 percent are classified as Severe.

Your National Weather Service considers a thunderstorm Severe if it produces hail at least 3/4-inch diameter, wind 58 mph or higher, or tornadoes.

Lightning

• Occurs with ALL thunderstorms
• Averages 93 deaths and 300 injuries each year
• Causes several hundred million dollars in damage to property and forests annually

Flash Floods/Floods

• The number ONE thunderstorm killer...near 140 fatalities each year.
• Most flash flood deaths occur at night and when people become trapped in automobiles.