The polar vortex may have left behind some giant boulders in its wake.

Giant ice balls appeared on the Sleeping Bear Dunes National Lakeshore in Lake Michigan. The beach-sized ice boulders were captured on video this week along the lake’s shoreline, MLive.com reports.

The balls are formed when water from the lake begins to freeze and is pushed ashore by wave action, according to AccuWeather.com Meteorologist Jim Andrews. As the waves come to shore, the ice tumbles and gets shaped into its round form.

"It's possible that the ice is accreting like a snowball or like a hailstone, and that they keep growing," Andrews said.

A YouTube video that surfaced this week shows the ice balls in action. Photographer Ken Scott caught the latest shots after he hiked half-mile from the road to get a good vantage point of the lake. He said the wind gusts that brought the temperature into the negative digits didn’t bother him.

"That's when some of the best shows are," he said.

The boulders, which are thought to weigh as much as 75 pounds, have appeared at Lake Michigan before. Photos of the ice balls were considered one of the “Most Amazing Earth Images of 2013” by the online magazine LiveScience. Leelanau County woman, Leda Olmsted, captured photos of the ice balls after seeing them in Sleeping Bear Dunes National Lakeshore in February. She posted the shots to her Facebook page where they soon went viral.

The latest video was taken in Glen Arbor, Mich. On Facebook it has received close to 2,000 shares.

“Snowy with a chance of meatballs!!” Facebook poster Linda Belil writes. “Couple of those would be good in a very large glass of bourbon,” another comments.

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