Flathead Range & Glacier NP

Generally stable conditions have people stepping out into big alpine terrain. That’s great! Ride with a good partner and keep them in sight. Steer clear of occasional recent wind drifts and steep, rocky terrain with variable, shallow snow cover to avoid triggering a very large avalanche.

Sunny skies above the stratus cloud deck caused a few small loose wet avalanches earlier in the week. Crusty conditions are likely on solar aspects. A few inches of new snow drifted into wind slabs at the highest elevations Tuesday and Wednesday. We have one report of a large wind slab avalanche that failed naturally on a cross-loaded, northwest-facing ridge near Heavens Peak. It likely ran in the last 48 hours. Windward aspects mostly harbor old wind board, thin, unreactive wind slabs, or faceted snow, which does not readily form slabs.

Mild weather and a hard crust found up to about 8000 feet have kept the snowpack quiet. Weak surface hoar and facets have developed around that crust, buried 2 to 8 inches deep. These will be important layers to track once they get buried.

The middle of the snowpack is strong and settled. Layers of facets and crust buried in early December have been gaining strength. The last reported avalanche failing near the base of the snowpack ran around the 13th. Snowpack tests performed below 8000 feet over the past 7 days have confirmed that those layers are less reactive.

There is more uncertainty above about 8000 feet. Another avalanche professional turned away from a fat line on Heavens Peak Thursday. He found terrible snowpack structure and poor stability. Large facets around a crust about a foot below the surface failed on isolation in his snow pit.  Other key factors from the highest elevations include a lack of information about the mid-January crust, and rocky, complex avalanche start zones that are more likely to have thinner, weaker snow cover. Deep, persistent slab avalanches remain a low-likelihood scenario, but the consequences are very high.