How is it Formed

Ice pellets falling from the sky.  Known as hail.   How does this happen? Why are they small sometimes and other times large and damaging?

As moisture gathers into the air from lakes, rivers, etc., they form cumulus clouds.  They start to condense as they gather more and more moisture.  As these clouds form, they become heavy.  These are called Nimbostratus and Cumulonimbus.  The clouds that create thunderstorms are the Cumulonimbus.  These clouds can build up to 50,000 ft. or more.

Inside veiw of the cycle showing how a hailstone is created

How a hailstone is created.

Did you know that the higher you go in the sky or atmosphere, the colder it gets?

Usually, with thunderstorms there is wind.  The only way for hail to form is if it has condensing moisture, cold temperatures, and nuclei, or something solid it can grab onto. There usually isn’t debris in the air, the wind provides the nuclei.  As the wind gusts along the ground, dirt, insects, etc., provide the nuclei the hail needs to cling onto.

Let’s explore, why some hail are smaller and some are bigger?  The size of the hail depends on how many times the starter hail has been brought back into the cloud to collect the freezing condensed moisture.  Hail needs debris to cling to, hail pellets create that second debris as it travels back into the moisture cloud.  What happens if you open a hailstone?  Well, you will see layers.  Just like an onion, on the outside, it just looks like a ball.  As you cut it open you will see rings.


Recently there was a report of hailstones 9cm in diameter in Northern Italy.  It did a lot of damage.  Shutters had huge holes in them, cars had damage, etc.  This would not be the time to venture out into the open air.  Try to imagine an object being hurled from an airplane.  As it falls, gravity pulls, and the hail falls faster and faster.  The biggest hailstone ever recorded was in Aurora, Nebraska on June 22, 2003.  It was 7 inches (17.8 cm) in diameter.  It would not be good to be outside in that weather. To see more articles and tips concerning weather go to www.weatheregg.com 

Large Hailstone on measuring tape

NWS Hastings pictures of the giant hailstones documented to have fallen in Aurora.

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