Hail

Hail is a form of solid atmospheric precipitation, distinct from ice pellets though the two are often confused, consisting of balls or irregular lumps of ice called hailstones that typically measure between 5 millimeters and 15 centimeters in diameter. Hail is possible during most thunderstorms, since it is produced by cumulonimbus clouds, and forms in environments of strong upward air motion within the parent storm together with a lowered freezing level; in the mid-latitudes it tends to form in continental interiors, while in the tropics it is largely confined to high elevations. Hailstones generally fall faster as they grow larger, though melting, air friction, wind and interaction with rain and other hailstones can slow their descent, and severe weather warnings are issued when stones reach a damaging size capable of harming structures and crops.