A snowmobile went through the ice in Vance Bay Lake Huron near the Town of Spanish on Dec. 26, trapping the rider in the freezing water for about 15 minutes.
Police, paramedics and firefighters were called to the scene just after 1:30 p.m. The 23-year-old was pulled from the ice by a friend and two other people who were fishing nearby.
"The person was transported to local hospital in Blind River for hypothermia," Ontario Provincial Police said in a news release Tuesday.
The Ministry of Environment was notified that the snowmobile was resting on the lake bed in about 30 to 40 feet of water.
"The OPP is warning snowmobilers that recent and current mild conditions have not helped with ice conditions," police said. "Not taking the necessary precautions can quickly result in tragedy … Underlying water currents or air pockets can create thin ice, even in the coldest temperatures. Snowmobilers can't see this until it's too late."