Classroom 9: What are hailstones and how they are formed

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SIOUX CITY, Iowa (KCAU) – For Wednesday’s edition of Classroom 9, I will be taking a deeper dive into one of the most damaging aspects of thunderstorms, especially when it comes to personal property like cars, and that’s hailstones!

Hail forms in a towering thunderstorm cloud and begins as a frozen water droplet.

Thunderstorms have a very strong upward motion which causes them to form what’s called an updraft.

The frozen water droplet cycles up and down in the thunderstorm cloud, passing the freezing level in the cloud repeatedly thanks to the updraft.

Each time the droplet goes back and forth across the freezing level, it gains an extra layer of ice which makes it bigger and bigger.

In fact, you can break a hailstone in half after it hits the ground and inside you’ll find a series of rings.

These rings can tell you how many times the hail bounced up and down inside of the cloud to gain its size.

Eventually, gravity wins because the updraft in the storm can’t keep the hail suspended anymore and it falls through the cloud to the ground.

Hail comes in a wide variety of sizes ranging from as small as a pea to as large as a softball!

Once a storm is verified on radar to have the potential of dropping hailstones over one inch in diameter, that’s when the National Weather Service will put out a Severe Thunderstorm Warning.

Since that’s when you can start to have major damage or injury happen from the hail.

The biggest hailstone ever measured in at eight inches in diameter!

It was verified by the National Weather Service and it fell in Vivian, South Dakota back on July 23, 2010.

Stay safe and seek shelter when hail storms happen!

When the storm is over you can put the hail in your freezer, if you want to preserve it.

Keep it tuned to KCAU 9 News and for more on your weather and Classroom 9!

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