When Mother Nature decides to make her own snowballs it's one of the most arresting phenomena of winter.
Also known as snow rollers, these quirky looking mounds of snow popped up recently in the fields near Wilbert on Highway 40 heading east. The snow rollers form only with the right combination of sticky snow, wind and temperature. Usually when winds get up to 30 km/h and are blowing the right direction, with the perfect texture of snow these tiny creations sometimes turn to big creations, rolling up just right with the ideal conditions.
This phenomenon has, of course, had all kinds of tales attached to it such as alien intervention, predictions of the remains of winter, moisture calculations for the coming year and the like. But for now it's just wonderful to experience and see.
According to web source, Wikipedia, "A snow roller is a rare meteorological phenomenon in which large snowballs are formed naturally as chunks of snow are blown along the ground by wind, picking up material along the way, in much the same way that the large snowballs used in snowmen are made. Unlike snowballs made by people, snow rollers are typically cylindrical in shape, and are often hollow since the inner layers, which are the first layers to form, are weak and thin compared to the outer layers and can easily be blown away, leaving what looks like a doughnut or Swiss roll."
The following conditions are needed for snow rollers 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;
Alternatively, gravity can move the snow rollers as when a snowball, such as those that will fall from a tree or cliff, lands on steep hill and begins to roll down the hill.
