Weather change increases avalanche danger

In its Feb. 7 advisory, the Flathead National Forest’s Flathead Avalanche Center warned that warmer weather coupled with strong winds and rain have increased avalanche dangers in the Flathead area.

“In many locations across the advisory area, temperatures failed to drop below freezing in the past 24 hours,” the advisory states. “Warm temperatures combined with moderate to strong wind and rain on a previously weak snow structure created dangerous avalanche conditions.”

The Center ranked the hazard high on wind-loaded slopes above 6,000 feet. Travel in this terrain and avalanche run-out zones was not recommended. The hazards in other terrain above 5,000 feet was rated considerable, and human-triggered loose, wet and storm-slab avalanches were considered likely.

According to the Center, a series of warm storms have moved through the Flathead, especially in the northern end of the advisory area, including Glacier National Park and mountains on either side of the U.S. canyon.

SNOTEL sites on Stahl Peak and Flattop Mountain recorded 1 to 2.9 inches of snow-water equivalent since the wet weather arrived, compared to 0.3 inches at the Noisy Basin SNOTEL site in the Swan Range during the same period.

Temperatures over the past 24 hours remained warm, with only Big Mountain and Flattop Mountain staying below freezing, the Center reported.

Natural avalanche activity was observed in John F. Stevens Canyon, Glacier National Park and Nyack Mountain on Feb. 6. Skiers in Canyon Creek in the southern Whitefish Range reported triggering a small storm-slab and also noted multiple piles of avalanche debris in the canyon, the Center reported.

“Yesterday, we were on Paola Ridge in the Flathead Range and found an upside-down storm-snow layer,” the Center reported. “At mid-elevations, this heavy, wet snow on the surface created a slab that was able to propagate a fracture within the recent snow. We triggered several storm-slab avalanches up to one foot thick while skiing down the ridge.”