Weather Wonders: What is Hail?
Discovery Place Science
Ever wonder how large chunks of ice fall out of spring and summertime thunderstorms? We call those chunks of ice hail, and they are signs and symptoms of intense thunderstorms!
Thunderstorms grow tall thanks to strong updraft winds, or winds that work their way vertically towards the tops of towering cumulus clouds. The updraft winds keep water droplets of the clouds in the coldest, freezing levels of the thunderstorm. Thunderstorms are so tall that at some point they hit temperatures below freezing way upstairs in the atmosphere.
As the updraft winds keep the frozen water droplets afloat, they continue to cool and collide into other droplets, growing each time. The stronger the updraft wind, the larger these frozen droplets, or hailstones, can grow.
Eventually, the weight of the hailstones becomes too heavy for the floating wind and gravity takes over. The hailstones drop out of the sky!
Large hailstones are signs of strong updraft winds in the most intense thunderstorms. While it is rare, hail can grow to the size of grapefruit in the most intense storms.
Severe Thunderstorm Warnings are issued when hail is at least the size of a quarter. Hailstones larger than quarters can create some serious damage to cars, roofs and buildings. They can crash through windows and injure people and pets, which is why meteorologists urge you to get inside and stay away from windows during severe thunderstorms.