Hail is precipitation in the form of ice chunks that fall from cumulonimbus clouds. It is commonly associated with multicell, supercell, and cold front-induced squall line thunderstorms.
Hail storms occur more frequently in the Great Plains states, especially northeastern Colorado and southeastern Wyoming, than in any other area of the United States. This area is known as Hail Alley. Hail typically falls here in the late afternoon during May and June.
The largest hailstone ever measured in the United States fell at Coffeyville, Kansas, on September 3, 1970. It weighed 1.67 pounds and measured 17.5 inches in circumference.