Weather Words: Snow Rollers

As the winter months begin setting up, keep your eyes peeled for something truly mesmerizing. Winter sometimes leaves us with tiny natural surprises, and one of the most whimsical is the snow roller. These are not the kind of snowballs you make with your hands — snow rollers are naturally formed cylinders of snow, created by wind and gravity working together in just the right conditions. They can range in size from a few inches wide to several feet long, and their hollow centers often make them look like giant cinnamon rolls or hay bales sitting in a snowy field.

Snow rollers require very specific conditions to form. First, the snow on the ground needs to be wet and sticky, but not so heavy that it collapses under its own weight. Then, a gust of wind or a slope can start the snow rolling, picking up more snow as it moves. The outer layers of the cylinder are usually looser, while the inner layers are compacted, giving snow rollers their unique, layered look. This delicate combination of sticky snow, wind, and gentle terrain is why snow rollers are so rare.

Despite their size and sometimes dramatic appearance, snow rollers are harmless. They can be fun to spot, and some people even photograph them as natural snow art. Because they are entirely dependent on just the right weather conditions, they often appear suddenly and disappear quickly, melting away in the sun or being crushed under fresh snowfall. Snow rollers are one of those fleeting winter phenomena that remind us just how creative nature can be.

Jennifer Gray is a weather and climate writer for weather.com. She has been covering some of the world's biggest weather and climate stories for the last two decades.