HELENA, Mont. — Rescuers searched Monday through the remnants of a deadly avalanche, unsure whether more backcountry skiers had been caught up in the slide in northwestern Montana.

Sunday's avalanche tore down trees and left snow 20 to 25 feet deep. Two skiers were killed, and rescuers pursued reports that two others might have been caught. But by Monday evening, no one had been reported missing.

Dangerous conditions delayed the start of Monday's search on Fiberglass Hill, a popular area on the other side of the mountain from Whitefish Mountain Resort. Authorities had to blast away an "unsafe snow mass" near the avalanche site, Flathead County Sheriff Mike Meehan said.

Once the search resumed, about 100 people used poles to probe the snow in an effort to find any victims. Dogs and a helicopter also assisted in the search, which was expected to last into the evening, depending on the weather.

The forecast called for high winds and snow after midnight.

The victims were identified as Anthony Kollmann, 19, of Kalispell, and David Gogolak, 36, of Whitefish.

Gogolak's body was found under about 3 feet of snow and debris. He was not wearing an avalanche beacon, according to the Missoulian newspaper. His brother-in-law was skiing with him and was partially buried but was able to dig himself out, according to the newspaper.

Witnesses were adamant that they saw two other people caught up in the slide, Meehan said.

As part of their search, deputies were checking cars parked overnight in the ski area to see whether anyone was unaccounted for, Meehan said.

Flathead County Undersheriff Pete Wingert said he did not know whether the brother-in-law could have been one of the two people searchers were looking for Monday.

The area is on U.S. Forest Service land, outside resort boundaries, said Donnie Clap, spokesman for Whitefish Mountain Resort.

"We set off explosions to mitigate the (avalanche) risk within our boundaries," he said. "When you ski out of bounds, you are really taking your life in your own hands."

In Wyoming, three men from that state, identified as Scott Bennett, Alan Jensen and Kim Steed, were killed in an avalanche while snowmobiling Saturday south of Jackson.

Avalanches have killed at least 21 people across the West since Dec. 2, according to the National Avalanche Center. 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.