Avalanche forecast

Tetons

Bridger-Teton Avalanche Center
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Avalanche danger

Thu
Alpine
3 · Considerable
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Out of date — this forecast expired 4 years ago.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 large avalanche is likely on steep, wind-drifted slopes in the upper elevations. This possibility also exists on upper-elevation slopes that are sheltered from the wind where new snow has bonded poorly. Cautious route-finding and conservative decision-making are essential anytime new snowfall is added to the equation here, or with changing surface conditions due to wind. While less likely, new snow atop older slabs could break up to two feet deep. 

Avalanche problems

  • Wind Slabs

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

    Though my forecast yesterday overstated the hazard based on higher snowfall amounts projected to fall throughout the day, I do think that triggering an avalanche with continued snowfall today in upper-elevation terrain (personally applying this beyond 10,500') will be likely. Continual snowfall into today will likely be heaviest around Teton Pass, and S-SW winds will continue to build wind slabs. These slabs will be thicker and more abundant as you climb in elevation. Windier locations like low saddles and mouths of main drainages are also likely to have denser, newly formed slabs sitting atop older wind slabs that still might remain sensitive to your weight. Loose snow movement is also likely in steep terrain, and the weight of this snow movement may also pose a threat for triggering a larger slab avalanche in adjoining terrain features (i.e. sidewalls of steep, tight terrain). 

    Sensitive slabs have been reported on steep E to NE aspects from 9,500’ to 11,400’. These reported avalanches have been less than 12 inches deep in isolated terrain features (Cave Couloir, Taylor, West Hourglass Couloir), and pose a larger threat in consequential terrain (Wister). Warming temperatures and changes in snowfall may make these slabs even more reactive. Also bear in mind that new snowfall can mask previously wind-loaded terrain and make unstable features harder to identify.

    (1/8/2023)

    Cave Couloir wind slab: 10,250' E apect

Avalanche Discussion

Managing Expectations

Yesterday's weather system was definitely not what I ordered at 5 AM.  It can be difficult to deal with managing expectations and dealing with uncertainty in backcountry skiing (and life generally). When the uncertainty is high-like with a weather forecast-the level of risk could be low, high, or somewhere in between. It's better to assume the worst and make your decisions accordingly. High uncertainty is the same as high risk, and at times we may feel very confident that the risk is high—on those days, decisions are easy. The days we wait, prepare, and plan for are both low risk and low uncertainty. Those are the times to go big and feel good about it. Today, my uncertainty is high in the forecasted weather, the lack of upper-elevation wind data, and how the newest snowfall is behaving.

In the Tetons, the amount of snowfall and rate matters, as most of our avalanche problems (and subsequent hazard rating) will be based on what is happening in the top part of the snowpack and with surface conditions. When either of these is changing, the terrain we seek out should also change. You might find it helpful to decide what is “off-limits” before leaving the house. This reduces the potential for other groups to influence your level of risk and also removes the temptation to accept more risk based on information (like tracks on a slope) that has no bearing on the stability equation. Build a safety margin into your travel plan and stick with it. 

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