Ever seen a ‘snow snail?’ Odd formation in Yellowstone caused by weather phenomenon

An incredibly rare weather phenomenon created mysterious snow formations in Yellowstone National Park.

Park officials posted a photo to social media Tuesday that shows multiple snowballs lined up at the bottom of a hill. The formations don’t look like your typical snowballs used in a snowball fight, though.

The snow looks like it could have been rolled on top of itself over and over again. Some people said they look like a cinnamon roll. Others said the formations look like someone remade snowman parts.

The photo highlights a rare weather phenomenon called “snow rollers.”

Snow rollers are known by multiple other names, including snow snails, snow bails, wind snowballs or snow doughnuts, National Geographic reported.

It’s an unusual phenomenon that happens when light and sticky snow gets pushed by strong winds, according to the National Weather Service. Sometimes they form by rolling down a hill.

“The snow rollers ... are extremely rare because of the unique combination of snow, wind, temperature and moisture needed to create them,” the National Weather Service said.

A light dusting of snow works best to form snow rollers, according to the National Weather Service. It has to be able to stick to itself but not the ground.

The formation is nearly impossible to replicate, which makes it even more rare.

In Yellowstone, the formation could be part of the transformation from winter to spring weather.

“Unpredictability characterizes Yellowstone’s weather, especially during the shoulder season,” park officials said. “Big temperature swings are possible and can be hard to predict.”

This story was originally published April 6, 2021 at 12:55 PM with the headline "Ever seen a ‘snow snail?’ Odd formation in Yellowstone caused by weather phenomenon."