11700207 - large hailstones on a black backgroundHail is one of the most damaging — and intriguing — types of precipitation. Have you always been a little confused about how ice can drop from the sky on a fairly warm summer day with very little warning? Here’s some Hail 101 for you.

The two basic ingredients needed to make hail are thunderstorms and updrafts. We’re pretty sure you are familiar with thunderstorms. Updrafts? They are upward moving air currents. A ground surface that has been heated by the sun all day warms the air around it, creating air that is less dense than air higher in the atmosphere. This air rises, and if teamed up with thunderstorm, it can rise high and quick. When these updrafts are strong enough to carry water droplets above the freezing point, viola!, you’ve got hail.

The weight of a newly formed hailstone will cause it to drop, but depending on how strong the storm’s winds are, these hail drops can get pulled high enough back up in the into the atmosphere to repeat the whole process. Each time a piece of hail is pulled back up into the atmosphere, its size increases. Just how big can they get? The largest recorded piece of hail in the United States landed on July 23, 2010 in South Dakota and measured 7.9 inches in diameter, 18.62 inches in circumference, and weighed in at 1.94 pounds!