Avalanche forecast

Tetons

Bridger-Teton Avalanche Center
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Avalanche danger

Tue
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Highlights

New snow and wind have made triggering a soft slab avalanche up to 18 inches deep likely in steep, wind loaded terrain at the upper elevations. Triggering a deeper avalanche that fails on weak layers buried 2-4 feet deep is unlikely, but not impossible. Be prepared to move to low angle terrain if you observe instability in the new snow such as cracking. Careful snowpack evaluation and conservative decision making are recommended around avalanche terrain today.

Avalanche problems

  • Wind Slabs

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

    Nearly 10 inches of new snow fell overnight in the Tetons. Moderate winds out of the west/northwest have redistributed this snow and formed soft slabs up to 18 inches deep in wind-loaded terrain at the upper elevations that are likely to be sensitive to the weight of a rider. Multiple skier triggered soft slabs were reported yesterday afternoon. Expect similar activity today. Be on the lookout for signs of wind loading including blowing snow and drifts. Cracking indicates unstable snow. Move to sheltered, low angle terrain if these conditions are observed.

    Wind slabs are less likely in the middle elevations. Here, new snow instability will likely be confined to loose sluffing in steep terrain.

    (1/4/2025)

    A small human triggered wind slab at 9,100'. Crown depth ranged from 4-12".  Similar activity is likely today in steep, upper elevation terrain that is wind loaded.

    Photo: Bridger-Teton Avalanche Center

  • Persistent Slabs

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

    Weak layers of snow are buried 2-4 feet deep in most mid and upper elevation locations. Triggering a large hard slab avalanche involving these layers is unlikely, but not out of the question. Recently, large triggers such as cornices or explosives have been required to initiate avalanches on buried weak layers. The last confirmed human triggered avalanche involving facets in the bottom third of the snowpack occurred on December 27th. Every reported persistent slab avalanche has occurred on the north half of the compass with east and northeast facing slopes being most active. Very steep (>35°), rocky, and unsupported terrain features are most suspect and should still be regarded with caution. Increase safety margins by travelling one at a time in steep terrain, conducting thorough snowpack evaluation, and maintaining good communication within your group.

    A large cornice triggered avalanche on the backside of Grand Targhee that likely occurred sometime around 1/3. This avalanche failed on weak snow deeper in the snowpack.

    Photo: Katie Cooney

Avalanche Discussion

A significant pulse of snow yesterday has kept new snow instabilities on the radar for another day. Be on the lookout for signs of instability and use caution around wind-loaded start zones in the upper elevations. 

The Tetons are on the tail end of a slow, but steady loading cycle. Measurable snowfall has been recorded nearly every day since December 23rd. Cohesive slabs of snow 3.5-4 feet thick lie above weak snow that developed earlier in the winter. In many places, the weight of a rider  is unlikely to impact the weak snow buried near the ground. Yet, it is important to remember that the snowpack is still under stress. Ten day cumulative snow water equivalent (SWE) values are just now peaking at 5.6 inches. This is a significant amount of weight and adjustment to loading takes time. Cornice and explosive triggered avalanches failing on deeply buried facets are reminders of what lurks below. Instabilities in the middle of the snowpack that developed around the Christmas storm have been largely unreactive over the past week despite snow pit tests showing mixed results. The snowpack will continue to adjust over the next week of relatively quiet weather and instability will trend downward. For the time being, it is important to maintain safe travel habits and approach steep terrain with a healthy dose of skepticism.

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