When a strong thunderstorm begins dropping hailstones it can often be surprising and many times terrifying, especially when the stones are large. They form when a raindrop is carried very high up within a thunderstorm cloud to extremely cold temperatures and freeze. They grow in size by colliding with other raindrops within the cloud and freeze to the surface of the hailstone. Hail drops from the cloud whenever the winds holding the hailstone high within the cloud can no longer support the weight of the stone and it falls. This means, the stronger the updraft winds (winds holding the hailstone up), the larger the hail will be.

Hail sizes can vary greatly, from the size of a pea to a grapefruit (and sometimes even larger). The largest hailstone on record was in Vivian, South Dakota on June 23, 2010. It measured a whopping eight inches in diameter and weighed nearly two pounds.

Nebraska, Colorado and Wyoming have the most hailstorms, however, hail can happen anytime there is a strong thunderstorm. Hail can severely damage homes, vehicles and anything else that it comes in contact with. Hail has also been known to cause injury and death to humans and animals. This is why it’s very important to seek shelter whenever there is a threat of severe weather.

Jennifer Gray is a weather and climate writer for weather.com. She has been covering some of the world's biggest weather and climate stories for the last two decades.