Officials say the two Iowa snowmobilers who were killed in a Colorado avalanche on Sunday were riding in a forbidden zone. The two eastern Iowa men were in a group of about a dozen, most of them from the Quad Cities area. The U.S. Forest Service says they were snowmobiling illegally, in a restricted wilderness area near Fort Collins where motor vehicles are banned.

Twenty-five-year-old Jacob Kroeger of Stockton and 32-year-old Gabriel Medina of Wilton suffocated after being buried in the snow. They were “high-marking” or racing up a snowpacked hillside, something that can trigger avalanches. The ten snowmobilers who survived may now face charges and if convicted, could see fines up to five-thousand dollars or six months in prison.