Not all volcanoes spew fiery molten rock. On rare occasions, in the cold dark winter, the shores of Lake Michigan can also belch up eruptions of slushy ice.
Recent photos shared by the National Weather Service in Grand Rapids have now captured these rare and fleeting 'ice volcanoes' in action.
"You never know what you'll find at the lake until you go out there," tweeted the NWS of Grand Rapids.
"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
Obviously, these aren't volcanoes in the geological sense. The icy mounds you see are actually created by powerful waves pushing under the lake's ice sheet; as the pressure builds, water and slush bursts through any available crack.
If the weather outside is just cold enough, this spray then freezes, building a volcano-like cone around the hole, which can climb up to eight metres high or, in some cases, even taller.
"It needs to stay cold enough to keep the ice around, and waves need to be large enough to force water upwards against the ice shelf," Cort Spholten, a Grand Rapids meteorologist, told Bisma Parvez from Detroit Free Press.
That doesn't happen very often. Besides, even when it does, these ice volcanoes are an ephemeral oddity, which is why they get people so excited when they do appear.
Tom Niziol, a winter weather expert at The Weather Channel, said these were some of the best photos of ice volcanoes he'd seen. But while they're certainly beautiful to look at, he also warned about getting too close.
"They can be very dangerous to climb on however because they are hollow and built over that hole in the ice," Niziol wrote on his Facebook page.
"Don't ever go venturing out onto them!!"
Remember: when you see an ice volcano, just marvel from afar.