Website home about our city
Picture of lightning

Thunderstorms, Lightning & Hail

What is it?

A thunderstorm is a transient storm of lightning and thunder, usually with rain and gusty winds, sometimes with hail or snow, produced by cumulonimbus clouds. A severe thunderstorm produces hail at least ¾-inch in diameter, wind 58 mph or higher, or tornadoes.    

Lightning is a luminous electric discharge in the atmosphere caused by the electric-charge separation produced in or thunderstorm clouds.     

Hail is a showery precipitation in the form of irregular pellets or balls of ice more than one-third inch in diameter.

What’s the Risk?

Thunderstorms affect relatively small areas when compared with hurricanes or winter storms. The typical thunderstorm is 15 miles in diameter and lasts an average of 30 minutes.

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

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.

Lightning occurs with all thunderstorms. There are an average of 93 deaths and over 300 injuries each year caused by lightning in the United States alone. In addition, there are several hundred million dollars of property and forest damage that result each year from lightning.

Hail, a frequent product of severe thunderstorms, causes nearly $1 billion in damage to property and crops each year nationwide.  Property damage estimates from hail in Colorado frequently top $50 million a year.

How Should I Prepare?


Preparations & Risks
Emergency Information