Avalanche forecast

Tetons

Bridger-Teton Avalanche Center
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Avalanche danger

Alpine
4 · High
Treeline
4 · High
Below
3 · Considerable
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Highlights

An avalanche warning has been issued for the area. Very dangerous avalanche conditions exist. Natural and easily triggered slides are likely today as a winter storm continues to load avalanche terrain. At the mid and high elevations, sensitive large slabs were formed by recent snowfall of nearly two feet of new snow and strong southwest winds. Even larger slides are possible at high elevations where the snowpack is underlain by old persistent weak snow layers. At low elevations, sustained rains or very wet snow has destabilized the snowpack and wet slides are possible in steep terrain. Yesterday many natural and triggered slides were reported. Several of these slides impacted roadways including one that knocked a vehicle off the road and onto its side on Twin Slides near the top of Teton Pass just before dark. Avalanche activity is certain today and travel in avalanche terrain is not recommended.

Avalanche problems

  • Wind Slabs

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

    Wind slabs formed by new snow and very strong southwest winds could be human triggered in steep wind loaded avalanche starting zones. These sensitive slabs could have depths to over three feet at the upper elevations and one foot at the lower elevations. They will increase in size and sensitivity as they are further loaded today. Veering winds to the northwest late in the day will also heighten this hazard.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    3

    Deep, hard slabs that lie over weak faceted snow and crusts near the base of the snowpack are being further loaded by this winter storm. These instabilities lie on west, north, and east aspects at the upper elevations. If initiated, the slides are likely to be very large with depths to six feet. Surviving such a large event is unlikely.

Avalanche Discussion

Bitterly cold, arctic air will become entrenched overnight with mountain lows in the negative teens. During the day on Saturday, highs will be in the negative single digits at the higher elevations. Snowfall will cease, cloud cover will decrease, and ridgetop winds will veer to northwest and decrease to 5 to 15 miles per hour.The general avalanche hazard is expected to be CONSIDERABLE on Saturday. Two avalanche problems will confront backcountry travelers. First, wind slabs with depths up to three feet, which formed during the most recent storm cycle, could be triggered by backcountry travels or release naturally on a variety of aspects above 7,500 feet. Second, deep persistent slabs similar to Friday’s events could also be human triggered or release naturally. The deep persistent slabs are confined to terrain that held snow from early October, but pose a much greater threat with slab depths that could exceed six feet. Conservative decision making and expert route finding will be essential for safe travel in avalanche terrain.

Regions covered