Hail forms when updrafts in a developing thunderstorm carry raindrops high enough in the cloud to reach the freezing level. Once frozen, the tiny frozen raindrop may make several trips up and down through the storm, growing larger with each pass.
Sometimes, updrafts in the storm can be as high as 100 mph. Under these conditions hail can grow to grapefruit size, until the updrafts weaken and they fall to the ground causing tremendous damage to property, crops and people.
