Snow rollers are being spotted in open fields throughout the Midwest. The unique snowballs and rolls are rare as they require a specific combination of conditions to form. Extreme cold and high winds throughout the region have provided the perfect environment for the rare formations.
The naturally occurring snow balls form where ice or ice-encrusted snow exists in a uniform layer over the ground. The surface layer serves as a platform where the balls are formed and can easily travel. The second layer, which rests on top of the ice, must be wet snow that is fluffy and loosely packed. This condition can be difficult to meet as wet snow is often quite dense.
In addition to the snow and ice, snow rollers require strong winds to form and propel the snowballs. As the wind scoops under the snow and pushes it along, the snow is shaped into unique formations. Some of the more common shapes are balls, donuts, and long formations that resemble jelly rolls.
As reported by Weather.com, snow rollers are often propelled by wind. However, some of the balls are formed by lighter winds and propelled down hillsides.
The unique formations often vary in size, depending on the amount of snow and how far they roll. The smallest are the size of a dime, but the largest can grow up to several feet wide. The average size is usually closer to 12 inches.
Although the formations appear similar to snowballs, they are not tightly packed. While they are interesting to look at or photograph, they usually cannot be picked up or held. Karen and Frank Ferguson found several rollers on their property over the weekend. They described the snowballs as quite "fragile" as they have "very little body to them... like meringue."
The rolled snowballs come in a variety of shapes and sizes. However, the most interesting and beautiful rollers have several distinct and visible layers. As the inner layers are the most fragile, the balls often have a hollow center. Therefore, the rolls with all layers intact are even more difficult to find.
The lines trailing behind the rolling snow can be interesting, as well. The trails are often similar to those left by rocks sliding through the desert in Death Valley.
The extreme weather in the Midwest has caused a lot of headaches for residents. Although snow is often an annoyance, phenomena like snow rollers remind us that the winter season can also provide some beautiful landscapes.
[Images via Flickr]