What are these snow formations?

snow

What are these snow formations? We have been cottaging for 40 years, and have never seen this phenomenon before.
—Evelyn Rancourt, Lang Lake, Ont.

According to our experts, these snow curls formed under a specific set of conditions: most likely, on a somewhat windy day after a light layer of freezing rain produced a thin crust over the field of snow. Because of the crust, the wind caused the surface to crack, rise, and then roll, a little like a carpet. If the wind had been stronger, it would have flung chunks of crusty snow across the field and chopped up the surface; if the snow had been loose—with no crusty surface—the wind would just have blown the snow into the air.

Wind can cause all sorts of wacky snow formations: Naturally formed snowballs that look like rolled logs or tubes (or sometimes like round hay bales in a hayfield) are called snow rollers.