Posted: Sunday, March 3, 2013 -- 8:28 a.m.

Information from the Rock County Sheriff's Department:

On 03/02/13 at 1:22am, Milton Fire Department along with Rock County Sheriff’s Office responded to Lake Koshkonong for a snowmobiler that had gone into the water. The location was offshore near the 11000 block of North Lakeview Dr, in Milton Township.

It was reported by a residence nearby of someone yelling for help. As Emergency crews were responding, a snowmobiler, Lewis Masterson, 46, of Beloit, came into the Countryside tavern who said he had gone into the water and walked to shore but his riding partner was missing. Fire and Sheriff Personnel arrived on scene at 1:45am and 2:19am. A location was narrowed and searches by Fire personnel and the Rock County airboat were started.

At 3:41am, the Rock County Airboat located the missing rider, in the water, approximately 300-400 yards offshore. Willie A Guzman, 47, of Beloit, was unresponsive and transported to Mercy Hospital by Milton EMS. Guzman was later pronounced deceased by Mercy medical staff.

According to Masterson, the riders became disoriented on the lake because of darkness and fog and traveled into an area of open water. Initial indications are that alcohol use was not a factor.

This is the 17th fatal snowmobiling crash this winter in Wisconsin. There were 10 fatal snowmobiling crashes last winter.