In December 2016, parts of New York saw a rare winter phenomenon: snow rollers. These are naturally occurring rolls of snow. The shapes can vary from fist-size snowballs, to large cylindrical rolls that resemble large hay bales. They are rare because you need several very precise conditions to get the ball rolling: wet, loose snow, a slick subsurface and a start to the ball. Most snow rollers occur in hilly areas, however in windy locations they can also form over frozen lakes or ponds. That is what occurred on December 19th, 2000 when residents of Russell County, KS were treated to the sight. Some of those snow rollers were as large as oil barrels.
Mary Knapp, Weather Data Library