Hailstorm

Hail falls on the back porch.
Hail falls on the back porch.

A long winter is coming to an emphatic end with a series of dramatic spring storms. This hailstorm from April 3rd was one of the most remarkable I’ve experienced.

Hailstone with a glove for scale.
Hailstone with a glove for scale.

There was a bit of discussion about just how big the hailstones were. After all, could we say that the hail was the size of golf balls if only the largest were? Or would it be more honest to go with some sort of median or modal size.

Mr. Schmidt and Dr. Hurwitz discuss the semantics and logic behind the qualitative reporting of hailstone size.
Mr. Schmidt and Dr. Hurwitz discuss the semantics and logic behind the qualitative reporting of hailstone size.

Mrs. F. brought out the calipers and a rule for a few of the larger stones.

Measuring hailstone diameter.
Measuring hailstone diameter.

And I will report that the hail was large enough to put small dents in the roof of my car.

Hailstones banging off the roof of the schoolhouse, and off the cars in the parking lot.
Hailstones banging off the roof of the schoolhouse, and off the cars in the parking lot.

The infra-red satellite image below shows the frontal system that dumped the hail on St. Louis.

Infra-red satellite image showing the clouds of the frontal system that affected St. Louis on April 3rd, 2014. Image from NOAA.
Infra-red satellite image showing the clouds of the frontal system that affected St. Louis on April 3rd, 2014. Image from NOAA.
Weather map for April 3rd showing the mid-latitude cyclone that produced the hailstorm.
Weather map for April 3rd showing the mid-latitude cyclone that produced the hailstorm. Image from NOAA HPC.

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