Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
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Avalanche danger

Sun
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 7 months ago. You’re viewing past conditions, not the current bulletin.

Highlights

Triggering an avalanche is unlikely on slopes with a strong supportable crust.  Move to lower-angle slopes if you or your machine start to break through the surface. Travel one at a time and watch your partner if your route crosses an obvious avalanche path or above a terrain trap.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2.5

    A layer of surface hoar (and facets) has produced natural and remote-triggered avalanches, whumpfs, and shooting cracks. Continued unstable snowpack tests indicate that this layer is slow to strengthen. Weak snow has been found on all aspects at mid- and upper-elevations, though obvious signs of instability have been most notable on slopes facing north and east. 

    On wind-loaded slopes, this layer is buried 1 to 2 feet deep, and the overlying slab could support the weight of a rider. Hard slabs of snow will differ from firm surface crusts in their chalky texture and may give a hollow, drum-like sensation. Slabs like this have the potential to break widely, or well above you, and are more difficult to escape. 

    On south-facing slopes, meltwater moving through the snowpack has the potential to cause wet-slab avalanches. This can be more common on slopes with exposed rock. Move off of and out from under steep, rocky slopes that are receiving direct sunlight, especially during the heat of the day. 

     

Avalanche Discussion

At least one recent observation found liquid water reaching the buried weak layer. Otherwise, it seems like meltwater has been slow to move through the snowpack. You can dig a quick hand pit to check on its downward progress today. Or consider meltwater a source of uncertainty and widen your safety margins on steep and rocky solar aspects. Although we have confidence in the distribution of the weak layer, the sensitivity is less certain. Reports of obvious signs of instability (cracking, collapsing, avalanches) have decreased during the three days, but this trend might be driven by poor riding quality and decreasing backcountry usage. Snowpack tests are still producing unstable results on many slopes, so exercise caution where the weak layer is present. 

Although we have another warm and sunny day on tap, we elected to remove the wet loose problem. Throughout the recent warm-up, wet loose activity has been stunted, with only small D1-1.5 slides reported. This trend continued on Friday, during Mark’s visit to the WMR sidecountry. Similar conditions were reported by an experienced pro near Lena Lake. While today’s temperatures are still expected to break records, we’re trending a few degrees cooler than yesterday, and it’s likely that any wet loose activity has run its course.

Regions covered