July 23rd marks the ninth anniversary of the largest hailstone ever recorded in the United States. It happened in Vivian, South Dakota back in 2010.
The hailstone had a diameter of 8″, and weighed almost two pounds! In the photo above and below, you can see how the hailstone punctured the ground.
Hailstones cause nearly $1 billion worth of damage to crops and property each year in the United States. Hailstones can fall faster than 100 mph at times.
So, what exactly causes hail? Frozen water droplets within the thunderstorm’s cloud are pushed even higher up into the cloud by a strong updraft (the wind moving upward into the storm). As the droplets are swept up, layers of ice form. Eventually, the ice accumulates so much where the updraft isn’t strong enough, and the hailstone eventually falls through the clouds and to the ground.
In order to get a hailstone with a diameter of 8″, you have to have a really strong updraft. The National Weather Service in Aberdeen, SD estimates the updrafts were as strong as 160 to 180 mph!
For comparison, here’s a look at some of the other common hail sizes.