A snowmobiler from Osage, Iowa died in an avalanche Tuesday near Togwotee Mountain Lodge at about 3:00 pm while three companions escaped injury. Teton County Undersheriff Bob Gilliam says 26 year-old Tyler Tourtlett had gotten his snow machine stuck about 1½ miles east of the lodge and a companion was circling around to assist him when the avalanche to released. Gilliam says the companion was able to ride out the slide and escape injury, while Tourtlett was swept into a tree and suffered severe trauma. He was also buried by the slide. Among those responding to the scene were Togwotee Mountain Guides, Grand Teton National Park Rangers, and Teton County Search and Rescue. CPR was immediately performed on Tourtlett but efforts to revive him were unsuccessful. Bridger-Teton National Forest avalanche forecasters say avalanche conditions over the past several days have been quite high with some of those that ran over the weekend being considered of historic proportions. Forest and county officials continue to urge back country users to continue to exercise extreme caution.