Snow Rollers. Rare conditions needed for snow rollers to form: 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;. Alternatively, gravity can move the snow rollers as when the snow falls from a tree, or high structure.The precise nature of the conditions required makes them a very rare phenomenon.