Avalanche forecast

Soldier & Wood River Valley Mtns

Sawtooth Avalanche Center
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Avalanche danger

Fri
Alpine
4 · High
Treeline
4 · High
Below
4 · High
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Out of date — this forecast expired 6 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Heavy snowfall and wind-drifting are creating very dangerous avalanche conditions. Natural and human-triggered avalanches are almost certain. Stay off of and out from below all steep slopes. Avalanches can be triggered remotely—from below, above, and to the sides of steeper terrain.

Avalanche problems

  • Persistent Slabs

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

    Today's snowfall and wind-drifting are stressing weak, faceted snow buried 2-3' deep. This weak layer has been the culprit in almost all of the avalanches we've observed this season. Continued heavy snowfall and wind-drifting will push this weak layer to the breaking point. 

    I urge you to steer clear of all avalanche terrain. Two years ago, and with conditions very similar to today's, a skier and a snowboarder were caught, carried, and buried in a slab avalanche outside the ski area boundary on Bald Mountain. Remember that once you duck the rope you're entering terrain that's unpatrolled and uncontrolled.

    (1/21/2019) Two years ago, and with conditions very similar to today's, a skier and a snowboarder were caught, carried, and buried in a slab avalanche outside the ski area boundary on Bald Mountain. Remember that once you duck the rope you're entering terrain that's unpatrolled and uncontrolled.

  • Storm Slabs

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

    This zone has received 2-3' of snow (1-2" SWE) since Tuesday night. Air temperature has continued to warm slightly as the snow piles up which aids in the formation of top-heavy slabs of snow on many aspects. These slabs are forming on a variety of weak snow surfaces including facets, crusts and facets, surface hoar, and wind-hammered ice. Yesterday, observers near Galena Summit reported cracking and collapsing of the snowpack, and conditions have deteriorated since. 

    Expect slabs to be thicker, stiffer, and more dangerous in windier terrain. Areas of wind-drifted snow may be hard to identify due to low visibility and continuing snowfall. This problem will become more dangerous as snow and wind continue throughout the day. These slides have the potential to "step-down" causing avalanches to fail on more deeply buried weak layers near the ground (see Persistent Slab problem).

    (1/27/2021) Cracking in freshly formed drifts along the Fishhook drainage in the Sawtooth Mountains. This photo is from early in the storm, conditions have considerably worsened since.

Avalanche Discussion

AVALANCHE WARNINGS are in effect for the Sawtooth & Western Smoky, Galena Summit & Eastern Mountains, and Soldier & Wood River Valley Zones. It continued to nuke snow in this zone last night adding an additional 0.6-1.2" of snow water equivalent in the last 12 hours. Heavy snowfall and wind-drifting will continue today.

Very dangerous avalanche conditions exist. Large, destructive, natural, and human-triggered avalanches are near certain. There are a host of scenarios that could send large avalanches hurtling down steep slopes today. Our snowpack has touchy weak layers under the recent storm snow, responsible for cracking and collapsing yesterday, as well as a remarkably weak foundation of faceted snow. Expect avalanches to occur on many slopes, potentially breaking in unusual locations and wider than expected. 

Avoid all avalanche terrain. This includes flat slopes in the valley bottom that are threatened from above.

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