The avalanche happened at about 1 p.m. Saturday on the north side of the Sheep Creek drainage of Loveland Pass, The Denver Post reported.
On Sunday, the Clear Creek Sheriff's Office released the names of those who died: Christopher Peters, 32, of Lakewood; Joseph Timlin, 32, of Gypsum; Ryan Novack, 33, of Boulder; Ian Lanphere, 36, of Crested Butte; and Rick Gaukel, 33, of Estes Park.
One member of the group managed to pull himself out of the snow and call for help, officials said. His name was not released.
Officials said this was the worst avalanche to occur in Colorado in more than 50 years -- in 1962 seven people were killed in an avalanche at Twin Lakes near Independence Pass.
Avalanche warnings had been high for the area because of unusual weather conditions for this time of year, when snowpack on mountains usually starts to stabilize, officials said.
"With all the snow and wind we've had over the last couple of weeks, winds are really building that slab up, and it's really kind of reached the tipping point this last week," said Colorado Avalanche Information Center Executive Director Ethan Greene.
"Especially in that area. We are very much in a winter snowpack right now. The calendar may say it's April, but the snowpack looks more like February and it needs to be treated as such."