The recent cold has built up shelf ice along the shore of Lake Michigan.
And people are being warned to stay away.
The Indiana Dunes National Park calls it “dazzling but deadly.”
It can be beautiful, at times, drawing people onto the ice, taking pictures and videos.
Dave Benjamin with the Great Lakes Surf Rescue Project says admire it from shore.
It may seem to be solid, but you never know what’s below.
The ice is constantly being broken up by waves.
It’s always thawing and re-freezing.
“What’s happening is we’re getting ice chunks fusing together,” Benjamin said. “Its kind of an unstable way for the ice to rebuild itself.”
Waves hitting the shelf ice create what are often referred to as “ice volcanos.”
They’re hollow mounds.
When waves hit, water spews from the top of the cones.
“These mounds can get very tall and that becomes another attractive nuisance where people see a hill, they want to climb it, but at the very top of this is going to be the weakest part, the part that formed last, and you could go through and now you’re in this ice cavern,” Benjamin said.
“Even if the water is only 2 or 3 feet it might be a height of 6 or 8 feet to try to climb out of. It’s an ice cavern, the walls are completely smooth, there’s nothing to grip on to.”
If you’re alone and you fall through, he notes, people may not hear your cries for help.
It can also be dangerous for dogs. They may try to get to open water and may not be able to make it back to shore.
Videos shared on social media, including drone footage shot by Timeless Aerial Photography, show people on the shelf ice in Michigan City.
“Are we seeing more people out on the ice or are we seeing more social media coverage of it?” Benjamin asked. “But then what we know is that social media coverage of something like this could cause more people to go out there because they want to get their Instagram moments.”
A statement from the Park Service says “though the ice may feel or appear strong, inconsistencies riddle shelf ice and thin spots may be hidden from view.”
It adds, “Do not risk your life! Stay on the beach and please keep off the shelf ice. As winter temperatures continually drop, shelf ice increasingly accumulates along the shoreline, and despite its unusual beauty, visitors need to be aware of its dangers.”