Hail

Hail is precipitation that forms when strong updrafts within a thunderstorm carry rain droplets into cold portions of the atmosphere. The supercooled water droplets collide with one another, creating layers and eventually forming a hailstone. These updrafts can be strong enough that it keeps the rain from falling to the ground. Hail stones can cycle in a thunderstorm several times before the stone becomes too heavy to be supported by the updrafts.

Severe hail is defined as having a diameter of one inch or greater, though small hailstones can cause significant damage too.