Holey rollers

By Phil Plait | December 23, 2009 7:30 am

I pay a lot of attention to weird things, and to weird weather. I thought I had heard it all: mammatus clouds, inversion layers, parhelic arcs.

But I can still be surprised! For example, I would’ve sworn up and down that snow rollers — giant rolls of snow that look like huge white Ho-Hos — were fake. But they are, in fact, real. Back in March, Tim Tevebaugh saw some in Idaho and snapped away. I couldn’t believe the photos, they’re so weird, I had to contact Tim. He kindly replied, and gave me permission to post pictures:


There they are, sitting on a plain. Evidently, wind conditions need to be just right, and the snow must be precisely the right consistency. I don’t think anyone has seen them form, but I suspect a small clump of snow gets picked up by the wind and rolls into a snowball. When it gets too big it collapses, starts rolling again, picks up more snow, collapses again, and eventually forms these long cylinders. It’s just a guess, but it seems logical. [UPDATE: several commenters have pointed out that the ball need not collapse to make a roller; I had supposed that happened to help spread the ball out horizontally. I stand corrected!]

Just how bizarre are these things? Here’s another picture:


If you look at the big one on the right, you can see how it looks like a piece of foam that’s been rolled up, a testament to how it formed. It like looking down the maw of the Doomsday Machine from Star Trek. I would love to see something like this as it happened. I’ve not seen anything like it in Boulder, but we’re getting plenty of snow here, and it’s plenty windy here so one day I hope to spot them.

I’m perpetually amazed at the imagination and creative power of nature. Snow rollers! Who knew?

Tip o’ the Frosty magic top hat to James Oberg and my thanks to Tim Tevebaugh for sending me the pictures and giving me permission to post them.

CATEGORIZED UNDER: Cool stuff, Pretty pictures, Science
MORE ABOUT: snow rollers

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