Avalanche forecast

Salt River and Wyoming Ranges

Bridger-Teton Avalanche Center
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Avalanche danger

Sun
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 2 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Human-triggered avalanches are possible at middle and upper elevations where weak layers below the snow surface exist. Avalanches may be triggered remotely -  from flat terrain above, below, and to the sides of steep slopes. Evaluate terrain carefully where winds have deposited additional snow.

Avalanche problems

  • Persistent Slabs

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

    The most recent snow has consolidated into 1-2 foot thick slabs in protected terrain and up to 3 feet thick in wind-loaded terrain. These slabs are sitting on various widespread weak snow layers including facets and surface hoar. The widespread nature of the weak layers means avalanches may be triggered on any aspect at middle and upper elevations. 

    The odds of triggering an avalanche are greater on the north half of the compass - where weak layers are well-preserved and winds formed slabs up to 3 feet thick. Signs of wind-transported snow include drifts, cornices, and textured snow surfaces. Persistent slab avalanches may not show signs of instability and can be triggered remotely from slopes above, below, or to the side of steep slopes. Use a wide safety buffer around steep slopes to address the uncertainty. Evaluate terrain carefully today. Even a small avalanche can have serious consequences.

    Warming Discussion: Warm ambient temperatures can increase the sensitivity of avalanches. As temperatures increase throughout the day, the likelihood of triggering an avalanche also increases. Small wet loose avalanches are possible today on sun-facing slopes. These will generally not be large enough to result in injury or burial.

    (12/15/2024)

    Remotely-triggered slabs failing on persistent weak layers. 

    Photo: Bridger-Teton Avalanche Center

Avalanche Discussion

The most recent storms brought 22-26" of snow to the Salt and Wyoming Ranges with over 2" of SWE in the middle and upper elevations. This new snow fell on weak layers that developed in December. As the new snow consolidates, it's forming a slab that could be triggered by a human. These persistent weak layers are tricky to identify from the surface and often will show no signs of instability before collapsing and causing an avalanche. Taking the time to dig into the snowpack will help you understand their distribution. Remember, if you find hard snow over soft snow, you have the anatomy for an avalanche. These layers take time to adjust. Now is an excellent time to familiarize yourself with them while the snowpack is thin and easy to dig into. Lower elevations are rated 'Low' due to the absence of old snow. Much of the early season snowfall melted at the lower elevations before our most recent storm. Low danger does not mean no danger though, old weak snow may exist in isolated pockets of protected terrain at low elevations.

Additionally, pay attention to warming snow on steep southerly slopes today. Yesterday, high daytime temperatures and direct sun were producing rollerballs and pinwheels on steep roadcuts and exposed rock. We have similar temperatures today. Increasing temperatures can increase the sensitivity of layers within the snowpack. While not listed as an avalanche problem don't underestimate the temperature's effect on the snow. Even a small amount of wet snow can prove problematic. 

Finally, remember that our snowpack is still thin. Even with the latest snow - rocks, logs, and other hazards may lurk just beneath the snow surface. The good news is we are sitting right around average now for precipitation totals, with more snow on the way.

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