This photo shows a large piece of hail.
Photo courtesy of Warren Faidley at www.weatherstock.com

Hail- Showery precipitation in the form of irregular pelts or balls of ice more than 5mm in diameter, falling from a cumulonimbus cloud.

Thunderstorms are usually accompanied by hail. The hail that falls from these storms is usually about the size of a pea and large hail is around the size of a softball. The largest piece of recorded hail to ever fall was the size of a melon, which fell in 1970.

Hail forms when currents of rising air, called updrafts, lift water droplets above the freezing level in thunderstorms. Then the water freezes into ice crystals and move around the cloud. When the crystals bump into each other they combine into larger ice chunks and eventually become too heavy for the cloud to hold. Strong updrafts can hold hail up longer, allowing it to form into bigger hailstones before it falls. The reason it may seem that hail doesn’t often occur during thunderstorms is because it usually melts before it reaches the ground.