Avalanche forecast

Salt River and Wyoming Ranges

Bridger-Teton Avalanche Center
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Avalanche danger

Mon
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Out of date — this forecast expired 4 years ago.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 a small avalanche is most likely in areas where wind of varying direction has deposited snow into firm cohesive slabs. Although less likely, large avalanches are also possible on buried weak layers of snow. Areas of the most concern are characterized by steep, rocky, and wind affected terrain that contains a shallow snowpack.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Variable winds of 20 mph over the last few days have created wind slabs at the upper elevations that are 1-2 feet deep. Low density snow is still available for transport, even though the area hasn’t received new snow lately. Slabs could be both soft and hard. Northerly and westerly winds will continue to dominate the forecast, so southerly aspects have the highest probability of encountering wind slabs. 

    Monitor the wind direction and pay attention to signs of instability such as cracking within wind drifted snow.

    (1/19/2023) Cornice at summit, this photo is looking NW.

  • Deep Persistent Slabs

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

    Widespread weak layers are buried  in the snowpack and vary in depth depending on aspect and elevation. On windward slopes these layers are 2-3 feet deep. On leeward slopes these buried weak layers could be in excess of 5 feet deep. Areas with a shallower snowpack have been easier to trigger a large avalanche. Dig down to determine how deep these layers are buried before committing to consequential terrain. Pay attention to signs of instability such as audible collapsing of the snowpack.

    (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

Avalanche Discussion

As you may have noticed, yesterday we transitioned from a Persistent Slab to a Deep Persistent Slab problem in the Tetons and Greys Forecast Areas. This debate seems to always be a challenging one for anyone in the avalanche world. The simple reason for this transition is when weak layers of snow are buried roughly over a meter deep. For most areas in the Tetons and Greys, we’ve hit this threshold. But the other important reason has to do with the unpredictable nature of these types of avalanches. As weak layers become buried deeper and deeper they become more and more difficult to trigger. Couple this with a snowpack of varying depth and sensitivity to triggering and this problem becomes even more difficult to predict. Simply put, the deep persistent slab problem is a way for us to characterize this unpredictability. The best way to reduce uncertainty is avoiding those thin, shallow areas with weaker layers where we have found unstable results in pits and actual avalanches. 

Northwest flow with little to no new snow will continue to dominate the area. These deep persistent slabs may seem dormant during these periods. Think about that low probability, high consequence scenario and pay close attention to large loading events of snowfall which could tip the scale to triggering these deep slabs. 

Regions covered