Snow cylinders are a rare meteorological phenomenon

Snow cylinders are a rare meteorological phenomenon in which naturally formed large cylinders of snow are moved by the wind, growing along the way. It's almost the same way we make snowballs for snowmen. But unlike snowballs made by humans, snow rollers are usually cylindrical and hollow inside. The inner levels are weak and thin compared to the outer levels and can easily crumble, leaving what looks like a doughnut or jam roll.









Snow rollers are formed in a combination of snow and strong winds, mainly in North America and Northern Europe, and they can be as small as a tennis ball, or large as a few meters in size – depending on how strong the wind is and how smooth the snow surface is. Gravity can also help form a snow roller. An inclined surface often requires just a small jolt from the wind to get this formation in motion.









The rolls are not hollow at the beginning, but as many levels grow, the roll gets bigger and bigger. Since the internal levels are weaker because they are formed first, they are easily deflated and form a cavity. Eventually, the rolls become too large to be carried away and stop when faced with any obstacle.










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