Avalanche forecast

Tetons

Bridger-Teton Avalanche Center
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Avalanche danger

Wed
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Out of date — this forecast expired 4 years ago.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

You’re most likely to encounter unstable snow on slopes with wind-drifted snow or shallower areas. New snow is adding additional stress to the weak snow buried deeper in the snowpack. Even on slopes sheltered from the wind, these weak layers create conditions that make human-triggered avalanches a possibility today. Be aware of this possibility and plan accordingly as you travel in the mountains today.

Avalanche problems

  • Wind Slabs

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

    Recent natural and human-triggered avalanche activity indicates that a recently buried interface in the upper portion of the snowpack is capable of producing avalanches. Winds have played a significant role in the slab formation portion of the avalanche equation in the past week. With the addition of new snowfall today and increasing wind speeds, additional slabs will form. Though older drifts are bonding to the surfaces that they were deposited on, the possibility of triggering one of the slabs remains, particularly in heavily loaded upper-elevation and middle-elevation terrain with cross-loaded features. These slabs are also adding stress to the weak snow described below.

    (12/19/2022)

    Skier-triggered avalanche in Jensen Canyon on a SE aspect around 9,600 feet.

    Photo: Mike Calla

  • Persistent Slabs

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

    Newly fallen and wind-blown snow continues to stress persistent weak layers buried 1.5-3 feet deep. These layers are widespread and are responsible for the majority of recorded avalanches so far this season. The sensitivity of these layers has decreased over time, but today a constant trickle of snowfall will continue to add stress. Though I do not expect snowfall amounts today to cause widespread instability, it's still possible to trigger a dangerous avalanche. If we go back to the basics, we have persistent weak layers that are getting loaded with new and windblown snow. It is likely some of these layers will hit a breaking point in the coming days as new snow continues to add up. Dialing back the slope angles before this happens makes sense. 

    (12/19/2022)

    Large natural avalanche on the E face of Static Peak

    Photo: Gavin Hess

Avalanche Discussion

With the holiday season fast approaching, I've found myself lately with a bellyful of cookies and margarine on the brain. Wait--make that margin on the brain.  A margin is essentially a buffer zone between you and a large amount of uncertainty that exists when traveling in any backcountry environment. The great thing about utilizing margin is that we can adapt ours as conditions change to include greater room for error. With incoming snowfall and high winds, all of our margins become smaller. We can offset this narrowing of our buffer zone by choosing terrain that is sheltered from current (and previous) wind-loading and dialing back slope angles early on throughout this storm.

The complexity of the snowpack is increasing as the season progresses, and another way to increase your margin is by keeping track of these layers in the areas that you frequent.  When dealing with persistent weak layers, even subtle changes in the snowpack can impact stability. Our margins can dictate how the cookie crumbles when dealing with multiple avalanche problems, incoming snowfall with wind, and uncertainty.  Be aware of the terrain that you are traveling through and underneath and think about the consequences of being caught in a slide in that terrain. 

 

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