A group of ice surfers are in hospital Friday evening after falling into the icy waters of Lake Simcoe, leading to a rescue by York Police and Georgina firefighters.

Acting Sgt. Kevin Smith of York Regional Police told ctvtoronto.ca that four of the five male ice surfers went through the ice of Lake Simcoe's Cook's Bay at about 5 p.m.

Of the four rescued from the water, "they're pretty cold. They're hypothermic," he said.

Three of the afflicted individuals went to hospital by land ambulance to a hospital in Newmarket, but a fourth has been taken by air ambulance. He has arrived at Toronto's St. Michael's Hospital.

The ice surfers used large kites to propel themselves along the ice, which was in bad shape due to the abnormally warm late winter weather. The temperature in the area reached 18 degrees Celsius on Friday afternoon.

"Who knows? I don't know why anybody would be out there," Smith said.

The Georgina fire department has an air boat that was used to get out to where the surfers had become immersed.  Five York police, clad in protective gear, went out on the ice on foot.

Smith said the officers broke through constantly on the way. "Everybody went through, but they're trained for it," he said.

The air boat brought the surfers back to shore.

Police strongly recommend that everyone stay off the ice, Smith said.

Provincial rules say that all ice huts have to be off the ice by March 15.