An avalanche advisory was extended through Tuesday in the Northwest Montana backcountry as dangerous conditions persist.

The advisory area included the Swan, Whitefish and Flathead Ranges, and the Lake McDonald and Marias Pass areas of Glacier National Park. Recent and drifted snow continue to overload a fragile layer in the snowpack. It will be easy to trigger large, wide and deadly avalanches, and natural avalanches may run long distances, the Flathead Avalanche Center warned.

The advisory from the Flathead Avalanche Center was first issued Friday as a potent winter storm entered the region.

On Saturday, Dave Cano, 59, of Kalispell was killed in an avalanche while riding in the Swan Range east of Kalispell.

Preliminary details from a fatal incident indicate that the snowmobiler triggered the slide in Wounded Buck Creek, north of Wildcat Lake. The rider was caught, carried and buried in the avalanche. The other three members of the party were also caught and partially buried, the report from the Flathead Avalanche Center states.

After extricating themselves, they searched for the buried rider up slope. Part of his pack was visible in the debris, allowing them to locate Cano and uncover him. Despite resuscitation efforts, the buried rider did not survive.

Bad weather and dangerous avalanche conditions prevented rescuers from reaching the scene that evening. Two Bear Air assisted with recovery efforts the following day.

Flathead Avalanche Center forecasters note that 15 people have died in avalanches in the U.S. in the last week, including the fatal incident in the Swan Range.

“This is the most avalanche fatalities in a seven day period since 1920,” the Flathead Avalanche Center noted in its Monday advisory. “Five of these events involved multiple burials and deaths. These accidents are a reminder for all of us to take a step back and be extra cautious.”

Most of the recent avalanches in the Northwest Montana backcountry have occurred on north, northeast and east aspects, and above roughly 5,800 feet in elevation.

“As you gain elevation, progressively dial back your terrain choices and avoid avalanche terrain altogether at upper elevations,” the advisory warns.

Visit www.flatheadavalanche.org for the latest advisory.