A huge avalanche at Whitefish Mountain Resort killed two backcountry skiers. Searchers combed the slide area for other possible victims.
Rescuers on snowmobiles head for the scene of an avalanche in Whitefish, Montana, on Sunday.
Emergency responders were alerted to the avalanche on Fiberglass Hill around noon Sunday.
More than 100 search and rescue people were quickly called to the scene.
"At this time, there are conflicting statements to responders about how many more victims might have been buried in the avalanche," Flathead County Sheriff Mike Meehan said.
The sheriff described the avalanche as "massive," and said the slide area is several hundred feet wide.
The avalanche began high on the mountainside and piled up between 25 and 35 feet of snow by the time it came to a stop, he said.
Avalanches have killed at least 17 people across the West since November 12. The national annual average for avalanche deaths is about 25.
Thirty-five people were killed nationwide in avalanches in the 2001-2002 season, the most on record, according to the U.S. Forest Service.