Avalanche forecast

Silver Valley & Bitterroot Mountains

Idaho Panhandle Avalanche Center
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Avalanche danger

Sun
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Your highest chances of triggering an avalanche will be in terrain that is steep, open and lacks vegetation. Storm snow and wind slabs will still be a concern at upper elevations where wind has compressed or transported the new snow and created slabs. An avalanche triggered in the new snow could step down to the deeper persistent weak layers and create a much larger avalanche. For the safest riding stick to terrain less than 30 degrees that is sheltered by the trees. 

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2–3

    Our current snowpack is harboring a persistent weak layer above 4,500' that can be found across the area on all aspects. This layer is close to the ground, it consists of crust layers and weak sugary snow that developed in early November. Stability tests are proving this layer has the potential to propagate and create avalanches that could fail 2 to 3 feet deep in the snowpack. Cracking and collapsing on this weak layer was observed this week across all zones of the forecast area. This problem is most likely to fail in steep and open terrain that lacks vegetation to anchor the snowpack (rocky or grassy slopes). Stability tests are also showing that thinner snowpacks will be more sensitive to triggers. Yesterday Silver Mountain Ski Patrol was reporting results on these deep weak layers during thier control operations. They were also seeing wide spread collapsing and "whumphing" across the mountain. 

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2

    Our latest storm has graced us with 1 to 2 feet of snow across the forecast area. This new snow is settling and becoming less of a concern as the storm exits the area. Storm slabs will become more resistant to human triggering with each passing day. Field observations were showing that the new snow will be mostly a concern in open terrain exposed to the wind, particularly near ridgelines. In terrain that is sheltered by timber the snow is light, soft and lacks the cohesion to create any storm or wind slab avalanches.

Avalanche Discussion

Moving into the weekend we will see clear skies and cool temperatures with winds becoming light and northerly. This switch in weather patterns will allow our most recent storm snow and loading issues to stabilize. My biggest concern looking into the future of our snowpack will be the weak layers close to the ground that continue to produce results in stability tests area wide. Currently this deep weak layer is making itself pretty obvious. If you experiece the snowpack collapse or see shooting cracks it's wise to stick to terrain angle less than 30 degrees.

Tuesday night through Friday morning the area picked up a fantastic early season storm. The new snow has created some excellent riding out there. Our snowpack is pretty bottomless still and lacks much of a base, so the potential to hit stumps and rocks is still very real, avalanches are not the only hazard out there right now. The other thing that comes to mind right now is with a thin and early season snowpack it is wise to be a little conservative in your terrain selection. Getting rolled in an avalanche is always bad, but it can be much worse in low snowpack conditions as you are likely to get scraped over the ground. Trauma is a very likely reality in early season avalanches. Our next scheduled advisory will be mosted Tuesday morning. 

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