EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

The growth of snow bedforms

Kelly Kochanski1, Robert Anderson2, and Gregory Tucker2
Kelly Kochanski et al.
  • 1University of Colorado - Boulder, Geological Sciences, United States of America (
  • 2University of Colorado - Boulder, Geological Sciences, United States of America

Wind-blown snow does not lie flat. It self-organizes into dunes, waves, ripples, and anvil-shaped sastrugi. These features, called snow bedforms, are high-speed analogues of sand features barchans, ripples, and yardangs. Snow bedforms appear within hours or days after a blizzard, and may migrate as fast as several meters per hour. They are widespread, and affect the albedo and thermal properties of snow across the polar regions, but thus far they have attracted little attention within aeolian geomorphology.

For the past three winters, I have documented the growth of snow bedforms in Colorado Front Range. I present time-lapse footage showing the movement of snow dunes, ripples and sastrugi (see These observations show that (1) snow is only flat when winds are slower than 6.4 m/s (2) snow dunes adjust minute-by-minute to changes in wind speed, (3) the most widespread bedform, sastrugi, evolve by migrating and eroding downwind, and (4) snow waves and dunes deposit layers of cohesive snow in their wakes, and thus aid snow deposition in windy conditions. These observations provide the basis for new conceptual models of bedform evolution based on the rates of snowfall, aeolian transport, erosion, and snow sintering across the snowscape.

How to cite: Kochanski, K., Anderson, R., and Tucker, G.: The growth of snow bedforms, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5918,, 2020