What’s up with those odd, circular shapes in the ice on Lake Michigan?
WGN Meteorologist Tom Skilling, of course, has the answer.
“What you’re looking at is pancake ice,” he said. The common phenomenon, he explained, is the result of blocks of ice breaking off and ramming into one another due to waves. The more they collide, the more a slushy rim builds around the edges of the blocks, causing the ice to appear like circular footprints.