Avalanche forecast

Salt River and Wyoming Ranges

Bridger-Teton Avalanche Center
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Avalanche danger

Tue
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate
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Out of date — this forecast expired 3 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

It is possible to trigger an avalanche 2-5 feet deep in steep, wind loaded terrain at the middle and upper elevations. Watch for thin rocky areas and wind drifted snow as they are most likely to produce a dangerous avalanche. Careful snowpack evaluation will be important today and conservative terrain choices are recommended.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2.5

    Snowfall and wind over the past two weeks have created thick slabs at the upper elevations. The recently formed slabs are sitting on weak layers of snow that can be found at different depths in the snowpack. Avalanches involving these weak layers could break 2-5 feet deep, or even deeper in some locations. Steep, rocky, and wind loaded terrain on the north half of the compass is most suspect. While the sensitivity of these layers is decreasing, natural and rider triggered avalanches occurred two days ago. These events indicate that the snowpack is still adjusting to the most recent load.

    Approach steep terrain in the upper elevations with suspicion. Extra caution is advised in exposed, wind affected terrain that is punctuated by rocks and cliffs. Obvious signs of instability such as collapsing may not be present. As a result, it is important to make your own stability assessment of a particular slope before committing to steep terrain. If you are unsure about a stability assessment, then defaulting to lower angle terrain is always a good call.

    (2/17/2024)

    This large avalanche was triggered by the second rider on a slope up Sheep Creek in the Snake River Range at 9,500 feet on an E aspect.

  • Wind Slabs

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

    Winds have built slabs 8-18” deep in exposed upper elevation terrain. Wind directions over the past several days have been variable. As a result, slabs could have formed on a wide variety of aspects. Suspect features include exposed ridges, rocky areas, roll overs, and gullies. Be on the lookout for wind affected snow on the surface that is stiff or drifted. Probing the snowpack for hardness changes (hard over soft) is a good way to identify these slabs.

    It is important to remember that a small avalanche breaking in wind drifted snow could step down to deeper weak layers resulting in a very large and destructive avalanche.

    (2/18/2024)

    The visual ripples in the snow surface and old drifted-in avalanche crown illustrate where some areas saw more wind, and any drifted or winded snow holds a higher potential for triggering an avalanche. 

    Photo: Gabrielle Antonioli

Avalanche Discussion

As the winter progresses, the Greys River forecast area has diverged into two uniquely different snowpacks. Areas such as the Salt and Snake River ranges possess a deep snowpack that is getting stronger by the day. On the other hand, portions of the Wyoming Range such as the Upper Hoback have a relatively thin and notably weak snowpack. Both of these snowpacks have just been stressed by significant snowfall since February 2nd. In the long term, the snow that we have received over the past two weeks is good news for stability. It has buried concerning weak layers deeply, and will promote healing in the snowpack. Unfortunately, the loading event is too recent to trust the snowpack at the moment. We are only two days out from a significant natural and human triggered avalanche cycle. The snowpack is still adjusting to the recent loading. This adjustment will take longer in areas that previously held a weak, shallow snowpack and the likelihood of triggering a large avalanche is higher there. Patients and conservative decision making are recommended while the snowpack adjusts. Building in an extra margin of safety to account for surprises is a good idea today.

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