Avalanche forecast

Soldier & Wood River Valley Mtns

Sawtooth Avalanche Center
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Avalanche danger

Wed
Alpine
4 · High
Treeline
4 · High
Below
3 · Considerable
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Highlights

An intense winter storm bringing 13-15 inches of snow and strong wind will overload a very weak snowpack. Very dangerous avalanche conditions will develop by this afternoon. Human-triggered avalanches large enough to bury you are almost certain, and very large natural avalanches are expected. Avalanches can be triggered from flat terrain a long distance from the slope. 

Conditions are much more dangerous in the western half of this zone —from roughly Dollarhide Summit and west into the Soldier Mtns and the South Fk of the Boise River drainage. For conditions in the Wood River Valley Mtns, refer to the forecast discussion. 

Avalanche problems

  • Wind Slabs

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

    13-15 inches of new snow will fall before 5pm today with strong winds. Winds will build very touchy slabs on all aspects at both middle and upper elevations. You'll find large, reactive wind slabs on many slopes today, thanks to the amount of new snow and the strength of the wind. Look for signs that the wind has been at work such as ripples on the snow surface, dune-like drifts, and fresh cornices. If the snow you are moving through suddenly becomes deeper and denser you've likely found a fresh slab. Cracks shooting out from your skis or machine are a clear sign the slab is unstable. Look for slabs near ridgelines and adjacent to midslope terrain features like ribs and gullies. In more sheltered terrain, expect to be able to trigger slides in softer, new snow. 

    Avalanches failing within the new snow will be effective triggers for deeper weak layers.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–3

    A layer of weak snow near the ground exists on many slopes. Today's windy and wild storm is pushing this weak snow towards its breaking point.  By the end of the day, triggering a destructive slide on this layer will become likely.  Avalanches that break on this layer could fail 3-5 feet deep, involving the entire snowpack. These will be large enough to not only take you out, but also could be large enough to bury a car. The likelihood of triggering one of these slides will increase dramatically throughout the day.

    Avalanches can be triggered from flat terrain a long distance from the slope.  Pay close attention to the terrain you are traveling through, but also to slopes you or others are traveling under. These slides will run longer than seen yet this season. 

Avalanche Discussion

A large storm pulse will bring 13-15 inches of new snow before 5pm today to the western half of this zone, accompanied by strong winds. This will fall on top of a very weak snowpack. Very dangerous avalanche conditions will develop by this afternoon. Human-triggered avalanches large enough to bury you are almost certain, and very large natural avalanches are expected. If you decide to head into the mountains today, be aware that avalanches can be triggered from flat terrain a long distance from the slope. This is the first large loading event our very weak underlying snowpack has seen this season.  Today is the day to expect the unexpected when it comes to slides — large paths can rip and run unexpected lengths. 

This forecast describes conditions where they are most dangerous —from roughly Dollarhide Summit and west into the Soldier Mtns and the South Fk of the Boise River drainage. The Wood River Valley Mountains (WRV) are only expected to receive up to 6 inches of snow. While avalanches are still possible in the WRV today, conditions are significantly less dangerous in this portion of the zone.

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