Avalanche forecast

Tetons

Bridger-Teton Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 2 years ago.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

Highlights

It will be possible to trigger avalanches in steep terrain in the mid and upper elevations today. It will also be possible to trigger avalanches remotely. Giving yourself a wide margin of error in avalanche terrain will be critical in avoiding getting caught today. Early season conditions exist. Being involved in an avalanche can result in significant injury due to rocks, vegetation and the ground lurking just below the snow surface.

Avalanche problems

  • Persistent Slabs

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

    Weak snow in the lower half of the snowpack exists in the majority of mid and upper elevation terrain. Slabs up to 3 feet thick rest on that weak snow and can be triggered in areas that developed wind slabs several days ago. Slabs 1-2 feet thick in the mid elevations also sit on weak snow and can be triggered primarily in terrain on the north half of the compass. In the lower elevations avalanches are unlikely except in isolated pockets that harbor old weak snow below the surface. 

    Recent avalanches, cracking and collapsing are obvious signs of unstable snow. These signs may or may not present themselves prior to triggering an avalanche today. Remote triggers continue to be observed. Hard slabs in the upper elevations could support significant weight prior to releasing. These slabs can break above a person, making escape difficult.

    Warm overnight temperatures that will continue to rise throughout the day will increase the likelihood of triggering, especially in terrain receiving direct sunlight. Small wet loose avalanches are possible today and will generally not be large enough to result in injury or burial.

    The best approach today is to be vigilant with safe travel practices. Travel one at a time, avoid steep rollovers, and utilize islands of safety when stopping.

Avalanche Discussion

While the number of avalanches has been on the decline since the most recent storm (Dec 15-17) and ensuing wind event (Dec 19), the possibility of triggering remains. This includes remote triggers. It also includes hard slabs that can allow a person, snowmobile or group to get far out onto a slope and trigger avalanches that break above. 

The weakest snow surface prior to the Dec 15 storm was in the form of facets with some areas of surface hoar. This interface, now buried 1-3 feet deep, is found predominantly in north (east through north through west) facing terrain in the mid and upper elevations. Terrain that lost the old snow due to warm temperatures and direct sun does not have this snowpack structure. Instead, that terrain is holding a generally more stable snowpack. Knowing the difference between these two set ups requires either a clear mental map of the pre storm surfaces or digging down and testing/observing the snowpack layering.

Unseasonably warm temperatures continuing today will increase the sensitivity of these slabs. Some upper elevation stations are reporting at or above freezing temps at 5 am this morning. While this contributes to short term instability, it also helps to promote strengthening as the snow surface cools and refreezes.

Regions covered