Nature is always showing us some interesting creations. In winter, one of my favorites is the snow roller. Haven't heard of it? It's not that common. When conditions all come together, the snow roller is fun to see.
Think of a snow roller as a rolled up slice of fallen snow. We need to have a windy day following a sticky, wet snowfall. But to be even more specific, the sticky, wet snowfall needs to fall on top of a crusty, snow covered area.
Snow rollers seen in Lincoln, IL. Photographed by Chris Geelhart. Courtesy of the National Weather Service.
Snowcover can get crusty when sunshine follows a fresh snowfall. The sun will melt the top surface of the new snow and a thin layer of water will sit on top of the snow. When the sun sets and temperatures drop, the thin layer of water freezes. If more snow falls on top of this crusty surface, and if the snow is wet and sticky, a strong wind may blow snow into rolls.
This unusual snow roller photo is courtesy of a FOX6 viewer, showing the snow roller on the windshield of a stationary car.
Snow rollers can be small - perhaps only an inch or two in diameter. Or they may be six inches in diameter. It all depends on snow consistency and stength/direction of wind. If you happen to see snow rollers, consider it your lucky day. They are a rare treat.