Avalanche forecast

Salt River and Wyoming Ranges

Bridger-Teton Avalanche Center
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Avalanche danger

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

It will be possible to trigger an avalanche 2-3 feet deep in steep wind loaded terrain at the upper elevations. Careful assessment of the snowpack will be critical in avoiding avalanches. Sticking to lower angle slopes while the most recent load continues to adjust will be essential today.

Avalanche problems

  • Persistent Slabs

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

    Snowfall over the last week has created slabs 2-3 feet thick. The recently formed slabs are sitting on weak snow above 8500’. These slabs have proven themselves to be most reactive in steep, wind loaded terrain on the north half of the compass. While instability on this interface peaked 3-4 days ago during a natural avalanche cycle, human triggered avalanches continue to be reported. Yesterday, three large avalanches involving this interface were remotely triggered by skiers in the Tetons. These avalanches indicate that the snowpack is still adjusting to the most recent load in some locations.

    Approach steep terrain in the upper elevations with suspicion. Extra caution is advised in exposed, wind affected terrain that is punctuated by rocks and cliffs. Be on the lookout for obvious signs of instability such as recent avalanches, collapsing, and shooting cracks. When these signs are present it is time to back off and choose simpler terrain. It is important to make your own stability assessment of a particular slope before committing to any terrain capable of producing an avalanche.

    (2/7/2024)

    This avalanche occured on Feb 7 in the Snake River Rangeon a NE aspect off a small ridgline at 8800'.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–3

    Above 7500’ hard slabs 3-5 feet deep lie above weak snow formed in December. Although the likelihood of triggering is decreasing, the possibility remains. Recent snow has added stress to these weak layers. Triggering a deep slab avalanche is most likely where the overlying slab is thin and riders can impact the weak layer. Any terrain with an overall shallow snowpack is concerning including very steep, convex, rocky and heavily wind affected slopes. Avalanches involving new snow could step down to these deeper layers in steep and sustained terrain.

    It will be easiest to impact weak snow from December in areas where the snowpack remains shallow. Parts of the Wyoming Range including the upper Hoback, Palmer Creek, and Little Greys still have shallow, weak snowpacks. The Snake and Salt River Ranges have deeper snowpacks making it more difficult to impact deeply buried weak snow. In these areas, the easiest way to trigger one of these avalanches will be with another avalanche that breaks in the most recent snow.

Avalanche Discussion

Spatial variability is a term that avalanche professionals like to use frequently. When talking about avalanches, it often means that stability can vary significantly in a small geographic area due to subtle changes in aspect, elevation, slope angle, and snow depth. This describes the current avalanche problem nicely. Last week’s storm brought a significant load to the mountains in a short period of time (1.5-3” SWE). In some locations, such as sheltered/sunny aspects, the new snow is bonding well to the old snow surface. In other spots, namely shady/wind affected terrain, the snowpack is taking longer to adjust. Recent remotely triggered avalanches are excellent evidence of this. Variability in stability means that it is important to make your own assessment of the snowpack before committing to steep terrain. Digging down to the most recent interface can be helpful, but also noting the characteristics of the terrain where you are riding is important. Red flags include the following.

  • Windy. Is there evidence of wind loading? Does the terrain seem exposed to the wind?
  • Steep. Is the terrain above 35 deg? Does it roll over?
  • Shaded. Nearly all of the recent avalanches have occurred on slopes with a northern tilt.
  • Rocky. Again, many of the recent avalanches have occurred in areas that are rocky or above cliff bands 

The interface that was buried on 2/2 was created by a week of warm, relatively dry weather. As a result, it is not terribly weak. The snowpack simply needs more time to adjust and stabilize. Continued vigilance and conservative terrain choices are recommended over the next few days.

Regions covered