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Lake Michigan's 'ice volcanoes' show up later than usual after warm January

“Ice volcanoes," or conical mounds of ice, occur when a wave manages to break through cracks in ice formed along the lake’s surface.
Image: An ice volcano erupts along Lake Michigan
An ice volcano erupts along Lake Michigan.Zoe Finney / Schlitz Audubon Nature Center

Ice volcanoes have formed along Lake Michigan after two winter storms in recent days have brought frigid subzero temperatures to some areas.

The icy mounds were spotted along the lake’s shoreline by the Schlitz Audubon Nature Center in Wisconsin, according to a post on the center’s blog. Typically, the ice volcanoes are seen in late January, and there was some speculation that the “ephemeral” wonders wouldn’t appear this year, Tom Finley, the center’s director of education said.

Though Lake Michigan may look calm under the ice shelf that forms in frigid temperatures, the water is bursting with life and motion underneath, Finley said. The moving water takes advantage of the imperfections in the ice floating above it.

“These bubbles of water come up through these holes and the holes are made bigger by the waves,” Finley said.”So the more cold, and the more strong the waves are, the better these ice formations.”

The Great Lakes haven't had nearly as much ice cover compared to years past, according to the National Oceanic and Atmospheric Administration. Only 2.4 percent Great Lakes surface was covered by ice by late January, the smallest amount in nearly 50 years. The agency also noted that it was ninth-warmest January on record.

Finley noted that the rising water levels in the Great Lakes and warmer temperatures have made the sight of ice volcanoes less frequent, and the formations rarely stay longer than a few weeks.

“It's interesting because I said that twice as strong waves helped create these formations, if it's super cold,” Finley said. “But strong waves will also break them apart, if it’s warm.”

Image: Ice volcanoes form along Lake Michigan.
Ice volcanoes form along Lake Michigan.Zoe Finney / Schlitz Audubon Nature Center

Though typically referred to as ice volcanoes, the term is a misnomer because they lack molten rock and gas, Atlas Obscura reported last year after a particularly late season appearance on the lake captured by the National Weather Service.

It’s unclear where the term originated from, Finley said, but the icy formations are actually able to grow in height because as they spew more water, the liquid freezes to help create the conical shape. It’s not unlike how lava cools to create volcanoes.

“It does look like a geyser, but because whey they’re in this ... quiet period, then they're just the ice itself left behind” Finley said. “And so then it looks like a lot the actual formation is cone shaped like a volcano.”

Finley has worked at the Schlitz Audubon Nature Center for about 20 years, a private nonprofit nature center with about 185 acres. The center focuses on conservation as well as education for people of all ages.

And while he considers ice volcanoes a fairly common feature of living on the shoreline of a Great Lake, Finley said he understands why people are so fascinated with them in a time where activities are limited by the coronavirus pandemic.

“Everybody is encouraged right now to get outside and be healthy,” Finley said. “It's good for your soul, it's good for your body, it's good for your mind ... so a lot more people I think than in the past are aware of things happening outside.”

But in freezing subzero temperatures, anyone venturing to go see the ice volcanoes should remember to proceed with caution. Finley advises people to cover exposed skin to prevent frostbite, make a plan to go with a group and inform others of the plan, and bring proper equipment such as walking poles and snow cleats.

“These are bitter cold temperatures,” Finley warned. “We're at, you know, -20 degrees with windchill. Most people wouldn't be out in that, but you can get frostbite quickly.”