Avalanche forecast

Snake River Range

Bridger-Teton Avalanche Center
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Avalanche danger

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

Human triggered avalanches are possible in very steep, wind loaded terrain at the mid and upper elevations. Wind slabs have the potential to break wider and deeper than expected. Conservative terrain choices are recommended today.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3

    A six hour period of moderate to strong ridgetop winds out of the southwest/south yesterday afternoon formed new soft slabs up to a foot deep in wind loaded upper elevation terrain. These slabs may still be reactive to the weight of a rider on very steep slopes today. 

    A week of heavy snowfall and strong wind formed hard slabs 2-4 feet thick that are resting on a widespread rain/rime crust that formed on December 10th. Very large avalanches involving this interface occurred within the last two days. The upper snowpack has settled and gained considerable strength since those events and decreased the likelihood of avalanches involving this interface. Today, surface avalanches may be enough of a trigger to initiate a larger more destructive avalanche. Avalanches involving the December 10th rain crust can propagate wide distances across slopes given the well connected nature of the bedsurface. Additional loading expected over the next several days will increase the chance of failure at this interface and will be monitored closely.

Avalanche Discussion

We are in a brief lull before the next loading event. Today is the first day without precipitation since December 17th. A series of powerful and warm storms over the last week have pushed the snowpack to its limits. Ten day snow water equivalent (SWE) amounts have plateaued just under 6 inches. As a result, we have seen large to very large avalanches failing on a variety of interfaces including hardness changes and a widespread rain/rime crust formed on December 10th. The avalanche hazard during these maritime storm cycles is quick to rise and quick to fall. The snowpack has undergone significant adjustment during the last two days without loading and signs of instability have decreased or are absent. Be wary of today’s lull. There is a good deal of uncertainty regarding avalanche potential on the December 10th rain crust. Very steep terrain should be approached with caution and thorough assessment today. More precipitation and loading is on the way and the avalanche hazard will rise in the coming days.

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