Hail is the product of severe thunderstorms.
It is caused by the freezing of raindrops inside a thunderstorm, where temperatures can drop to more than 30 BELOW zero!
As the tiny drops of frozen rain continue to circulate inside the storm cloud, more layers of water coat the ice pellets and then freeze.
Depending on the number of times a layer of water forms, then freezes, a hailstone can grow quite large before it finally falls to the ground.
Proof of this can be found by slicing open a large hailstone.
There, you’ll see layers, much like an onion, showing how the hailstone developed aloft.