"A snow roller is a rare meteorological phenomenon in which snowballs are formed naturally as chunks of snow are blown along the ground by wind, picking up snow along the way. To form, the ground must be covered by a layer of ice to which snow will not stick. The layer of ice must be covered by wet, loose snow with a temperature near the melting point of ice. The wind must be strong enough to move the snow rollers, but not strong enough to blow them too fast. The precise nature of the conditions required makes them a very rare phenomenon."
How cool is that?PS I'm not bragging about my photography here . . .