Avalanche forecast

Salt River and Wyoming Ranges

Bridger-Teton Avalanche Center
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Avalanche danger

Thu
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Snowfall and strong wind yesterday will continue through today, rapidly loading terrain and adding stress to buried weak layers. Triggering an avalanche 2-3 feet deep is most likely on wind-loaded slopes facing north-northeast. Persistent slab avalanches are difficult to predict and could be triggered remotely from gentle terrain above, below, or beside steep slopes. Due to dangerous conditions, stick to lower angle slopes and avoid steep, wind loaded terrain.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–2

    Weak layers formed during the January drought are the biggest concern today on wind loaded terrain. Triggering a soft to hard slab avalanche 2-3 feet deep is possible, and more likely on northerly aspects where the weakest layers have been stressed by wind loading. The highest concentration of the avalanche activity over the last week was from 8,000-9,500’ on N-NE aspects. Persistent slab avalanches are difficult to predict and won't necessarily present obvious signs of instability such as shooting cracks or collapsing. These weak layers have a scattered distribution meaning some slopes may appear stable while others are not.

    A snomobile triggered avalanche near Togwotee Pass that occurred on 2/13. Triggering a slab like this is possible in isolated pieces of terrain in the Salt/Wyo Ranges.

  • Wind Slabs

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

    Up to a foot of snow has fallen in the last 48 hours in locations favored by the storm. Strong winds have varied in direction from south through west. This has formed reactive wind slabs 1-2 feet deep across the middle and upper elevations on cross-loaded and leeward terrain. Due to the strong intensity of wind, these slabs may be reactive further down slope than expected. Watch for large drifts, shooting cracks, and stiffened snow surfaces as signs of wind loaded slopes. 

    An additional 6-8 inches of snow is possible by this evening.

    Example of how to identify wind loaded terrain. 

    Photo: Bridger-Teton Avalanche Center

Avalanche Discussion

The extended dry period in January formed weak layers of facets and surface hoar on terrain sheltered from the sun and wind prior to its initial burial. This made these weak layers scattered across various slopes, where some areas harbor weaker and more reactive layers. Managing this problem is difficult without thorough snowpack assessment and actually determining if and where these weak layers exist. What we do know is that these layers have been most reactive on the northerly slopes mentioned above. Unfortunately, these slopes are also being rapidly loaded by southerly wind and increasing the likelihood of triggering a large, consequential avalanche. 

Prior to this storm, many areas in this zone did not have enough snow to create a firm overlying slab above weak layers to produce avalanches similar to the Snake River Range and Tetons. As new snow accumulates, a firm overlying slab will form increasing the potential of buried weak layers breaking wider and further than expected. Today is not a good day to test your luck on steep slopes as the snowpack adjusts to changing conditions. Travel one at a time and limit your exposure on or around avalanche terrain.

Regions covered