Avalanche forecast

Salt River and Wyoming Ranges

Bridger-Teton Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 3 years ago.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

Highlights

Triggering a dangerous slab avalanche on a deeply buried persistent layer, particularly in steep, wind-affected terrain is possible today.  Riding and skiing on a thicker snowpack unaffected by the wind and off of steep and rocky terrain will greatly reduce your chance of triggering an avalanche.

Two cornice failure incidents occurred yesterday, one of which resulted in a significant fall. Cornices are large and sensitive to triggering right now.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2.5

    The persistent slab problem exists at all elevations and most aspects. Steep, rocky or wind-affected terrain should be approached with caution or avoided all together in favor of lower angled terrain less likely to contain rocks and thin spots. Thin areas in the snowpack are where you are most likely to impact buried weak layers currently 2-5 feet below the surface. The depth and structure of the snowpack varies in the Greys River zone, and the best way to verify the location of weak layers is to dig or probe. When in doubt, choose lower-angle terrain and watch out for large slopes above you that could avalanche and run further than you expect. 

     

    (2/17/2024)

    This rider trigger avalanche near Sheep Pass occurred on Saturday. The rider was caught but not buried. 

  • Wind Slabs

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

    Recent snow and wind from last week and last night formed wind slabs 1-2 feet thick on a variety of aspects at upper elevations. Watch for stiff pillows and drifts around exposed terrain such as ridges, rocky areas, convexities and gullies.  Shooting cracks, hollow sounding surfaces, and collapsing indicate unstable snow beneath you.  Ride in sheltered terrain where signs of wind-loading are absent to avoid this problem.

    Small wind slab avalanches have the potential to step down and impact deeper weak layers which could result in a large avalanche. See photo. 

    (2/19/2024) Wind loaded slope which failed on persistent weak layer on Palisades Peak.

  • Cornices

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

    Light density snow and moderate wind speeds have built very large, overhanging cornices that are becoming more sensitive to triggering in the warm temperatures.  Two incidents occurred yesterday near Grand Targheeand in the Big Holes. Give cornices a wide berth, more than you think, and look for rocks and brush underfoot to confirm that you have solid ground beneath your skis or sled. Cornices can break further back than might expect. They can also serve as the heavy trigger needed to impact a deeply buried weak layer. 

    (2/21/2024)

    Cornice failure at the top, crowns in the center, flanks below the cliffs outlined in blue.

    Photo: Daniel Nagy

Avalanche Discussion

Avalanche forecasts become overly complicated and difficult to apply to terrain choices when there are multiple avalanche problems listed. Cornice fall appeared on the list of problems today in order to highlight an issue which has been discussed from time to time in the wind slab avalanche problem. Cornices are not difficult to identify and avoid, but can be unpredictable in the ability to cling to steep terrain. Most of the time they aren't a widespread problem until significant warming. The two incidents yesterday and maybe the very large avalanche on No Name over the weekend may be a trend towards a wider problem, or maybe these incidents are a coincidence. In any case, these cornices have grown large this season and are a growing concern and will likely continue to be another low probability, high consequence hazard to keep on your radar.

As the sun's azimuth angle continues to increase, brief periods of sunshine  decrease the stability of the snowpack and relatively warm air temperatures do the same.  The period of unsettled weather this week that will persist through the weekend brings the chance of clearer skies than forecast. Keep track of this solar gain when you are out and about. While it doesn't seem likely that we'll see wet avalanche activity given the forecast, direct sunshine or greenhousing can decrease stability quickly though temporarily. 

Regions covered