From ice balls to ice volcanoes – Lake Michigan is clearly as cold as ice.

The Holland State Park in Michigan posted on social media Friday that its shoreline was covered in “ice balls.” The post included a photo of hundreds of large, round chunks of ice lining the shoreline.

The strange weather phenomenon typically occurs earlier in the season but last week’s polar blast finally brought temps down far enough.

It’s cold as balls out here! Seriously, if you’re coming out to see the ice balls, please dress warm and be careful of snow covered debris. Posted by Holland State Park on Friday, February 14, 2020

The boulder-sized balls form when chunks break off from sheets of ice covering the lake, and the churning waves form the pieces into balls.

But experts urged caution for those looking to see them for themselves.

“Seriously, if you’re coming out to see the ice balls, please dress warm and be careful of snow covered debris,” the state park’s post read.

In another strange, icy moment along Lake Michigan, the National Weather Service Grand Rapids tweeted images of “ice volcanoes” erupting along the lakefront at Oval Beach Sunday.

“You never know what you’ll find at the lake until you go out there,” the tweet read. “Today it was volcanoes.”

It was a great day to visit the beach and watch the waves interact with the ice. Here's a couple "ice volcanoes" erupting at Oval Beach on Sunday, February 16, 2020. #miwx #wmiwx pic.twitter.com/B0Vkl18RrN — NWS Grand Rapids (@NWSGrandRapids) February 16, 2020

You never know what you'll find at the lake until you go out there. Today it was volcanoes. Here's a close up: pic.twitter.com/FLZqDZ1d8U — NWS Grand Rapids (@NWSGrandRapids) February 16, 2020

The Wisconsin Department of Natural Resources says the rare sight happens when “a shell of ice forms and a weak spot is exploited by the wave action, creating a hole.”

“Then a volcano-like structure forms around the hole from the water being sprayed from the top,” the department wrote on Facebook.

It's not the first time such weather phenomenons have been spotted along Lake Michigan.