Approximately cylindrical, natural accumulations of snow, with diameters that sometimes reach 300 mm, and a similar length, which lie at the end of meandering tracks. They arise when an old, moderately cohesive snow layer is covered by a layer of new, uncompacted snow, followed by a rise in temperature and a moderately strong wind. Small, initial clumps of snow are blown downwind, growing as they travel. A slight gradient appears to assist in the rollers’ formation.
Subjects: Meteorology and Climatology.