Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
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Avalanche danger

Wed
Alpine
1 · Low
Treeline
1 · Low
Below
1 · Low
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Out of date — this forecast expired 3 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Signs of unstable snow have dropped off over the past week. Despite the good stability, on northerly facing slopes at upper elevations, a weak snowpack structure still exists. If you decide to enter steep terrain, the best practice is to do so one at a time while having a spotter in a safe location.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1–2

    Isolated wind-sheltered and shaded terrain above about 7000 feet harbors a weak snowpack. Either avoid steep, consequential slopes that fit this description, or test them with dropped cornices or large column tests. Cracking, triggered slides, or propagation in tests are signs you’ve found a slope where your weight can trigger an avalanche. A person is less likely to trigger a slab avalanche in areas where you find a thick, supportable crust under roughly 1 to 2 feet of snow.

Avalanche Discussion

Observations over the past week have generally described stable avalanche conditions. The only reported red flags are signs of localized cracking around skis or boards, which predominately occurred in wind-drifted snow. The recent avalanche activity has been relatively benign. We received reports of mostly small loose snow avalanches, and one skier-triggered wind slab avalanche last week. This slab avalanche was also small in size. If you have not yet, take a look at the Visual tab on the new observation platform, located here. This is an incredibly useful tool that helps paint a picture of what everyone is reporting to us out in the mountains. 

Although we are seeing generally safe avalanche conditions, we are also still finding a weak snowpack structure in areas. The type of structure we are concerned about is where the 12/7 crust becomes thin and breakable, and where a weak layer of surface hoar lurks below. You can find this weak layer by first locating the crust. The crust is a good identifier in the snowpack, and is commonly found buried beneath 1 to 2 feet of soft snow. If you dig below this crust, roughly 1 to 8 inches further down, you can sometimes find this finicky weak layer by its visual appearance. Surface hoar is typically seen by a grey stripe in the snowpack. This layer of surface hoar has ranged from very easy to find, to more difficult to find. This is the setup I am still steering away from. 

The areas where a person may find this problem are in the uppermost reaches of the forecast area, and in areas where we have a deeper snowpack. Some of those areas that come to mind are the crest of the Flathead Range, around Mt. Aeneas in the Swan Range, and the higher peaks in the N. Whitefish Range. Most other areas have a thinner snowpack, or the 12/7 crust is thick and supportable, thus making it less likely for this problem to exist. 

Regions covered