Monday, May 24, 2010

Turtle hail?

Cell phone photo courtesy of John Lindenberger

Monday night's hailstorm in North Platte dropped some decorative ice sculptures, all thanks to Mother Nature.

Shawn Jacobs, meteorologist at the National Weather Service in North Platte, said it comes down to collisions.

"One hailstone is recycled up and down through the updraft of the storm, collecting moisture and collisions in the atmosphere with a bunch of little hailstones," Jacobs said.

He said super-cold water droplets freeze in the updraft as the hailstone is repeatedly pulled up and down and those droplets attach to the main hailstone. At this point, the hailstone is still held in the air by the updraft.

As the stone makes many trips up and down through the updraft, and the super-cold moisture collects on the single stone, it's possible to have very smooth hailstones, or maybe one that is shaped like a cauliflower. Or, in the case of the ones John photographed, you can imagine the shape as that of a turtle.

I think the one on the left looks a little like a swimming penguin.

What do you see in the photo?

Jacobs said eventually the hailstone, with all the little hailstones and the super-cold water droplets attached, becomes heavy enough with its load that it will overcome the updraft and drop to the ground.

Caution: Don't run outside to gather hailstones while the storm is in progress. No matter how interesting the shape of the hailstones, they hurt like everything if you get hit with one on its way to the ground.

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