Avalanche forecast

Silver Valley & Bitterroot Mountains

Idaho Panhandle Avalanche Center
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Avalanche danger

Sun
Alpine
2 · Moderate
Treeline
1 · Low
Below
1 · Low
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Highlights

Expect elevated avalanche conditions today as a storm brings new snow and moderate winds. Human triggered avalanches are possible. For the safest riding, consider wind-sheltered terrain. Avoid slopes with fresh wind slabs and give them a wide berth. 

Avalanche problems

  • Wind Slabs

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

    Overnight snow in the Silver Valley zone was minimal, but more snow is forecasted for this morning, so it’s important to consider potential new snow problems in your travel plans, particularly in wind-loaded areas. Silver Mountain recorded average winds of 15 mph overnight, with gusts exceeding 35 mph. The new snow is interacting with various old snow surfaces, making the reactivity of the new slab variable. Watch for signs of instability, such as whoomphing, cracking, or natural avalanche activity. Additionally, the new snow is adding weight to a persistent weak layer about 12 inches deep in the snowpack. As more weight is added to this layer, the closer it gets to a failure point. Skier-triggered avalanches, either in the storm slab or on the persistent weak layer, are possible today on slopes over 30 degrees, especially on wind-deposited slopes.

  • Persistent Slabs

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

    The hardness and thickness of the upper rain crust varies across our forecast zones and has been found up to about 6,500 feet. Where the crust is around 2 inches thick or more, weak grains have been reluctant to fail in snowpack tests. Places where the crust is thinner and breakable, tests continue to produce failures with moderate to hard force. Your odds to trigger a deeper, more dangerous avalanche may increase as you move higher in elevation where the overlying crust is less supportive or non-existent.

Avalanche Discussion

New snow across all zones today should be your primary concern. The snow surface the new snow fell on varies depending on location, elevation, and aspect. Some surfaces yesterday were firmer and smoother, while others were rimed and had a rougher texture. These varying surfaces may interact differently with the new snow. There is some uncertainty until forecasters are able to assess how the new snow is bonding to the old snow in the field. Areas where wind has deposited the new snow are the highest concern. Wind-loaded snow tends to be denser and heavier, adding stress to underlying weak layers. It's best to avoid wind-loaded slopes today. Be vigilant for signs of instability and monitor changing conditions as you move through the mountains.

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