When the Coast Guard responded to a call around 3:30 p.m. the man was not in the water anymore, but was wet and suffering from hypothermia. He was able to tell rescuers that he was the only one that had been in the water.
Exactly why the man was out on the lake is unclear. He was taken to University of Chicago Hospital in serious condition, suffering from hypothermia and other conditions related to being in the water for some time.
Fire Department and Coast Guard responded to the scene after seeing a report of a man who had fallen through the ice about 60 feet from the lake shore.
"Any ice-- it doesn't matter where you are, how long it's been frozen-- is extremely dangerous, unpredictable. You don't know how thick it is," said Petty Officer John Palmer, U.S. Coast Guard.
How long the man was in the water is unclear, but with the frigid temperatures in Chicago, any time in the water is a serious situation.
This was likely a challenging rescue, given poor visibility with the lake effect snow.