A hailstorm hits without warning. It batters the roofs of houses and shatters windows, dents cars, and destroys entire crops. With beads of ice pounding the ground at more than 60 mph (100 km/h), hail is probably the most destructive precipitation on Earth. Hailstorms rarely occur in hot countries because the hailstones melt long before they reach the ground. Hailstorms happen mainly during the spring and summer months in temperate zones, which are areas with four different seasons. They develop during thunderstorms and very humid weather, when winds are strong enough to hold up the hailstones that form in the clouds. The central region of North America is the area most often hit by hailstorms. In Colorado in 1984, a storm left the people of Denver with hailstones up to their knees!
Hailstones are usually about the size of peas, but they may be as large as grapefruits. At this size, they become weapons that can seriously injure humans and animals. The biggest hailstone ever found in the United States was the size of a honeydew melon!
Hailstones are formed inside cumulonimbus clouds, where freezing water droplets are put in motion by strong winds. This is how a hailstone is formed:
Layers like an onion
Hailstones move up and down inside cumulonimbus clouds for 5 to 10 minutes before falling to the ground. While traveling inside the cloud, they may pick up as many as 25 layers of ice.
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