Hail is frozen pellets of ice that can be as small as a pea, as large as a grapefruit and anything in between.
This gives hail a dangerous, destructive capability that makes it hazardous for people and crops, especially delicate crops like wheat. In fact, research shows that hail causes more than $1 billion dollars of damage each year.
The potential for hail first begins when moisture evaporates from the earth’s surface and rises into the sky. As the moisture-rich air continues to rise, it reaches an altitude where the air temperature is below freezing. This transforms the moisture into tiny pieces of ice called nuclei. Strong updrafts can keep the nuclei in the air and allow them to grow by accumulating additional moisture. These layers appear like rings in a tree and can be seen by cutting a hailstone in half once it has fallen to the ground.
Hail often falls during thunderstorms. That’s because thunderstorm clouds are full of freezing moisture, making them the perfect partner for hail nuclei. As the hail nucleus comes into contact with a thunderstorm cloud, it accumulates this additional moisture much more rapidly.
Hail that remains in the thunderstorm cloud long enough will eventually grow too big and too heavy to be kept aloft by the currents. Gravity will then force the hail down to earth, leading to a hail storm.
Ever wonder where hail most commonly falls? Find out in the next post.