Avalanche forecast

Salt River and Wyoming Ranges

Bridger-Teton Avalanche Center
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Avalanche danger

Tue
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Triggering an avalanche is possible within the new snow as well as weak layers of snow buried 2-4 feet below the surface. Recent snow and wind varied drastically across the forecast zone over the last 24 hours adding stress to these buried weak layers. The southern portion received 10 inches of new snow and will have increased sensitivity to both small and large avalanches. Use heightened caution in areas with increased snowfall amounts as the snowpack adjusts to this recent loading.

Avalanche problems

  • Persistent Slabs

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

    Weak layers of snow are buried 1-4 feet deep. Areas that received higher amounts of new snow last night could experience increased sensitivity to triggering a large avalanche. These layers can be broken down into two main categories:

    1). Surface hoar layers in the upper portion of the snowpack are buried 1-3 feet deep depending on the elevation. Unstable test results in snow pits have confirmed these layers are particularly sensitive. This layer is difficult to manage due to its scattered distribution and reactive nature. Digging a snowpit in one location may not identify this layer. Use extra caution in terrain sheltered from the wind where this layer was preserved and buried. 

     2). Persistent weak layers formed in November and December are buried 2-4 feet deep near the base of the snowpack. These weak, sugary facets are widespread across most aspects and elevations with increased sensitivity in terrain with a shallow snowpack. Reactivity of these layers has decreased over time, but the poor structure still exists. Recent loading of new snow could stress these layers beyond the tipping point and increase sensitivity.

    (1/5/2023)

    This avalanche was triggered by a rider at Jack Hollow on a southeast aspect at 9,500 feet.  It failed on weak snow in the lower half of the snowpack and was approx. 3 feet thick. 

    Photo: Antonioli

  • Wind Slabs

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

    New snow amounts varied across the zone in the last 24 hours with up to 10” of new snow favoring the southern portion of the Greys. Wind slabs previously formed before this new snow may still be sensitive to triggering 1-2 feet in depth. These slabs could be hidden beneath new snow or freshly formed wind slabs 2-3 feet in depth in isolated areas with high amounts of new snow. Upper elevations on exposed terrain or along ridges will be the primary concern. Variable winds recently could make identifying wind loaded terrain difficult. The highest likelihood of encountering a wind slab will be on north and east aspects, although variable winds could load unsuspecting terrain. 

    In addition, storm slabs could be sensitive in areas with higher amounts of new snow. These slabs will be less than a foot deep with increased reactivity on southerly aspects where new snow fell on melt freeze crusts. 

    (1/12/2023)

    Cracking, an obvious sign of instability. 

Avalanche Discussion

Variability is the best way to describe today's avalanche danger. The majority of the terrain out there will likely have mostly stable conditions. But, thanks to the unpredictable nature of weather systems we will see a mixed bag of avalanche conditions. As you’ve likely noticed if you read this far, snowfall amounts varied drastically across the Tetons and Greys forecast zones.  The main debate this morning is whether considerable avalanche danger will be found in the upper elevations in these isolated areas of significantly larger snowfall totals. You may very well find these heightened avalanche conditions out there even though the overall danger rating is moderate (a spicy moderate as some say). The reasoning behind maintaining the moderate rating is the spatial distribution, small avalanches in specific terrain or large avalanches in isolated terrain. Think about those specific or isolated areas with significantly more snowfall before planning and choosing terrain today.

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