Rare winter phenomenon: Snow rollers
Snow rollers, a rare natural occurrence, were spotted in Fairfield, Idaho, this week. The rollers are formed when strong winds pick up moist snow and carry it along the ground, gathering more snow and forming cylinders. The largest rollers may be as big as barrels.
According to the National Weather Service, these are the ideal conditions for the formation of snow rollers:
- Existing icy or crusty snow cover, so additional snow will not stick to it.
- Additional wet, loose snow on top of the icy, crusty snow cover
- Wind strong enough to scoop out balls of snow and propel snow roller foward.
- At least some slope to the ground.
Additonal snow roller photos: Rare Snow Rollers Spotted in Idaho