An online resource based on the award-winning nature guide

Snow Rollers

1-2-17-snow-donuts-049a2495Once in a great while nature provides us with a spectacular display of snowballs littering the surface of  flat, snowy fields or woodlands. These rounded structures, called snow rollers or snow donuts (there is often a hole in the center of them), require a precise balance of air temperature, ice, snow, moisture and wind in order to form.

To begin with, the ground surface (typically quite level) must have an icy, crusty snow, on which new falling snow cannot stick. On top of this, there needs to be about an inch of loose, wet, sticky snow. The air temperature needs to be around 32 degrees F. Last, but not least, there must be a strong, gusty wind blowing 25 miles per hour or more. Snow rollers begin to form when the wind scoops chunks out of the top inch or so of snow and these chunks roll, bounce and tumble just like tumbleweeds, downwind. They gather additional snow as they roll and become larger and larger until they are too large for the wind to push. Snow rollers can be as small as a tennis ball or as much as two feet in diameter, depending on how strong the wind is and how smooth the surface of the snow is. There can be hundreds of them in a field or patch of woods. When a snow roller starts to form, there is no hole in the center of it. As it picks up speed and snow, the thin center often crumbles, forming snow “donuts.” (Thanks to Judy Howland for photo op.)

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11 responses

  1. Terry Ross

    Mary If the rollers are on a church lawn are they now Holy Rollers? Terry

    January 2, 2017 at 9:51 am

    • But of course, Terry! Love your quick wit. 🙂

      January 2, 2017 at 10:38 am

  2. Cynthia Tate

    Hello MmmmmO, have you ever seen this phenomenon before? I don’t think I have… I sure miss snow, snow, snow. Din, Cmmmmmm >

    January 2, 2017 at 10:44 am

  3. Guy Stoye

    Snow-rollers fascinating. In the three years I lived in northern Ohio, surrounded by mostly open land, I NEVER saw (or at least noticed) such a thing. Will be alert for them from now on in New Hampshire

    January 2, 2017 at 11:12 am

  4. Sandra Holland

    Love this. Look a lot like the huge rolls of hay. A fun phenomenon!!!

    January 2, 2017 at 11:38 am

  5. Viola

    Nifty phenomenon. What a privilege and fun to find!

    January 2, 2017 at 1:17 pm

  6. whwurm2017

    Never saw this before and yet we had ice flowers on our frozen lake 2 weeks ago. Again, they need just the right conditions, temperatures below 5F is one of them. If I could figure out how to attach a photo…

    January 2, 2017 at 11:54 pm

  7. whwurm2017

    Mary, these are the ice flowers I was talking about in my comment to your last blog. They appeared on December 20th after a very cold night and stayed for over 24hrs when the temperature went up. Some seem to form around foreign bodies, others just over rough spots on the ice.

    Heinrich Wurm

    Lovell, Maine

    These are the

    January 3, 2017 at 12:04 am

    • Heinrich, did you send me a photo? WordPress doesn’t let them come through and I would love to see it if there was one. Could you send it to me at mholland@vermontel.net? Thank you!

      January 3, 2017 at 8:48 am

  8. Jon Binhammmer

    I’ve seen these also on very steep slopes, so wind is not a required element, but temperature and gravity are!

    January 3, 2017 at 11:04 am

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