Snow rollers are rare natural phenomena where cylindrical snow formations are created by wind, gravity and specific snow conditions.
Some Interesting Facts
- Snow rollers form under unique weather conditions
- Have been found in other countries as well, including Europe and Canada
- They come in sizes from a few inches to several feet in diameter
For much of the country this winter, it has turned out to be quite harsh, with outbreaks of arctic air pushing southward, creating dangerous conditions. And as is usually the case, the cold is accompanied by periods of snow and ice.
After a fresh snowfall, many find it beautiful as it covers the landscape in a white blanket. However, in the urban areas especially, road grime and dirt quickly turn the pure white snow into an unsightly mess.
However, sometimes a strange phenomenon can appear in the countryside. Snow structures resembling rolled-up carpets or jelly rolls can seem to suddenly appear out of nowhere in open fields. What are they, and how in the world did they get there?
Snow rollers are a fascinating meteorological phenomenon that occurs under very specific atmospheric and surface conditions. Their formation is governed by physics, particularly the interplay of wind force, friction and gravity. They are most commonly reported in open fields, hillsides, and mountainous regions during late winter or early spring.
Wind plays a crucial role in initiating the rolling motion. However, it must be strong enough to push the snow, but not so strong that it scatters or breaks it apart. If the wind isn’t sufficient, gravity can also cause snow to roll downhill, forming a natural spiral as it picks up more layers.
• The snow must be in a semi-wet state, meaning it has enough moisture to stick together but not too much that it collapses under its weight.
• The presence of an ice crust underneath ensures the rolling snow does not adhere to the ground, allowing continuous movement.
• The temperature should be around freezing or slightly above (32°F or 0°C), which allows the snow to remain cohesive.
Small Rollers – Resemble compacted snowballs, often just a few inches wide.
Large Rollers – Can reach several feet in diameter and may be hollow in the center because of the way they form.
United States:
• In 2009, a large number of snow rollers were spotted in eastern Washington after a storm created perfect conditions.
• In 2014, residents of Ohio and Pennsylvania reported fields full of snow rollers after a unique weather event.
Europe:
• Snow rollers have been recorded in the Scottish Highlands and parts of Norway, where wind-driven snow is common in open landscapes.
Canada:
• The Prairie provinces and parts of Ontario have occasionally reported snow rollers, typically after warm snowfalls followed by high winds.
Because of their rarity, snow rollers often surprise people who are unfamiliar with them, sometimes leading to mistaken reports of “alien activity” or unusual natural events.