Avalanche forecast

Tetons

Bridger-Teton Avalanche Center
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Avalanche danger

Alpine
4 · High
Treeline
3 · Considerable
Below
2 · Moderate
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Out of date — this forecast expired 7 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Avalanche conditions remain elevated due to yet another day of snowfall and strong winds. Two weak layers are buried deeply within the snowpack. The older weak layer was buried on November 25th and the more recent layer was buried on January first. Large to very large avalanches could be triggered on these layers. In addition to these deep instabilities, backcountry travelers could trigger newly formed wind slabs and loose snow sloughs. Avalanche hazard is highest at the upper elevations where travel is not recommended. At the mid elevations, cautious routefinding and avoidance of steep terrain is the best way to avoid the avalanche danger. At low elevations, watch for specific terrain features that are loaded and beware of the run out zones of large avalanche paths.

Avalanche problems

  • Wind Slabs

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

    Strong southwest winds and new snow has formed shallow wind slabs in steep leeward terrain. These slabs lie upon recent density breaks within the upper portion of the snowpack and could have depths to twelve inches. They could release naturally today, particularly at the higher elevations as they are further loaded by new and blowing snow. Human triggered soft slabs and loose snow sloughs could be easily triggered in steep terrain. Although initially small, these events could sweep the unsuspecting over rocks and also entrain large volumes of snow.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3

    Hard slabs could be triggered by moving surface snow or by the weight of a person impacting a weak spot on a slope. These slabs could fail on two distinct weak layers. The higher layer was buried at the start of the new year and could release with depths of two to four feet at the upper elevations and with depths to two feet at the lower elevations. This buried weak layer lies on a variety of aspects and is made up of surface hoar, buried faceted snow, and on south facing aspects, crusts. A deeper pronounced weak layer was buried on November 25th. This hazard is limited to north facing terrain at 8000 feet and as elevation increases, involves more aspects. At 9500 feet west, north and east facing slopes can have this weakness. If triggered, slabs involving this layer could have depths to six feet.

Avalanche Discussion

Snowfall is to increase again tonight and be heavy at times between midnight and 5pm Tuesday. Another ten or more inches of snow is possible during this time. Southwest winds are expected to have averages between twenty-five and thirty-five miles per hour with higher gusts. Temperatures are to remain cold at higher elevations with lows in the single digits and highs in the low teens. The avalanche danger will likely remain High at the upper elevations of the Tetons and could increase to High in the Southwest Trails and Togwotee Pass areas depending on the amount of new snow and wind received overnight and through the day. Wind loaded slopes will be sensitive to backcountry riders and skiers on a variety of aspects and elevations and could release naturally. Slabs are most likely to initiate as newly formed soft slabs but the potential also remains to trigger deep weaknesses in the snowpack. These slabs could fail after a soft wind slab is triggered or possibly by the weight of a single person finding a weak spot on a slope. Slab depths could vary from on foot to six feet at higher elevations, depending on which layer fails and on snow depths in that location. At lower elevations, slabs to two feet could be triggered.

Regions covered