(Calumet County) It was a deadly weekend for snowmobilers with five people killed in separate incidents. In Iron County, a 43-year-old woman died shortly after being hospitalized when her sled collided with a semi-truck on Friday. A snowmobile operator was killed Saturday afternoon on Lake Winnebago in Calumet County after striking a snowbank or ice crack and the machine landed on them. Three fatalities occurred Saturday night. In Dunn County, a 28-year-old man died when he lost control of his sled and was thrown off. In Langlade County, a 41-year-old woman died after her snowmobile struck a car. In Forest County, a person died after they were ejected from their sled and struck by another snowmobile. The DNR is investigating in partnership with state and local law enforcement agencies.