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Move to Colorado from another state and an unpleasant surprise awaits: the price of car insurance. Your premiums will very likely be higher here. Why? Hailstorms.

Hail forms during thunderstorms, and Colorado has more thunderstorm days than any other state except Florida. The state’s mountains and high elevation increase the likelihood that hail will form in a thunderstorm, making Colorado one of the hail capitals of the world. Northeastern Colorado and nearby Great Plains states get more hail each year than any other part of the United States.

Hail damage to crops, roofs, and cars is part of life in Colorado, but some storms are worse than others. The second-costliest hailstorm in U.S. history hit the state on July 11, 1990. Hailstones the size of marbles to tennis balls pummeled the Front Range for three hours as the “7-11 hailstorm” moved from Estes Park to Colorado Springs. Damage totaled more than $600 million dollars, mostly affecting roofs and cars.

How Does Hail Form?
A hailstone starts as a tiny ice crystal in a thundercloud. As the crystal falls through the cloud, it collides with water droplets that freeze around it, like the layers of an onion. Updrafts push the hailstone back up, and it continues to grow.

The more times the hailstone goes up and down, the larger it gets. When it gets too large for the updrafts, it falls to Earth. Scientists estimate that it takes 100-mile-an-hour updrafts to form a baseball-size hailstone.

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Photo credits: © Corbis Images, © NCAR, © NOAA, courtesy NEWS4, Colorado's news channel.