Bollettino valanghe

Salt River and Wyoming Ranges

Bridger-Teton Avalanche Center
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Pericolo valanghe

Tue
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 2 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Triggering a 1-3 foot slab avalanche is most likely on wind-loaded slopes. New snowfall equals additional weight on weaker layers of sugary, faceted snow that are buried on most middle and upper-elevation aspects. Although less likely, triggering avalanches is still possible on slopes sheltered from the wind. It remains possible to trigger avalanches from above, to the side, or below steeper slopes. Assess the snowpack you are moving in, particularly if riding both sunny and shady terrain at upper elevations.

 

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Weak, faceted snow exists in layers at the base and middle of the snowpack on most mid to upper-elevation slopes. This snow is buried beneath slabs that are now 1-3 feet thick and exists on multiple aspects but is most prominent on the northern half of the compass. The snowpack in much of this zone remains shallow and reactive and is currently experiencing change in the form of new snowfall and wind today. Any change means sticking to simple terrain and ruling out steeper slopes can reduce your chances of triggering an avalanche. Persistent weak layers are difficult to deal with. They can produce avalanches many weeks after they are buried and provide fewer obvious signs of instability as the days pass. They can break wider than expected and may be triggered remotely from gentle terrain adjacent to steeper slopes. 

    Noticing firmer snow over softer snow with pole probing or poking around in a sled trench is another great way to look below the surface and help you identify if weak snow exists on the terrain of your choice. Recent avalanches, cracking, and collapsing are obvious signs of unstable snow. These signs may or may not present themselves prior to triggering an avalanche today. 

    (12/20/2024)

    This avalanche was remotely triggered up Murphy Creek near the Stewart Massive ~8300' on a NE aspect on 12/20. 

    Photo: Second-hand report to Bridger-Teton Avalanche Center

Avalanche Discussion

Areas of favored snowfall (the Salt) are expected to increase in hazard throughout the day. Portions of the Wyoming Range receiving less snowfall will trend toward the lower end of this hazard rating. We are starting to see a fair bit of variability in the way different sections of this zone are behaving. However, there is an unfortunate constant across the region: a layer of very weak snow that developed during early December is capable of producing remotely triggered avalanches, even days after snowfall. The variation between sections of this zone is driven by how deeply this snow is buried by a slab, as well as how much snowfall existed prior to the larger storm cycle last week. 

In addition to the depth of burial, the nature of the snow above these weak facets is important. In areas where the wind has helped to stiffen the overlying snow, you are much more likely to experience cracking and collapsing and to be able to trigger an avalanche. In areas where the snow above is soft and unaffected by the wind, you are less likely to see these obvious signs of instability. Bear in mind that the new snowfall today may be masking signs of previous wind loading. If the character of the snow you travel through changes from soft to firm, the likelihood of triggering an avalanche increases. Unfortunately, even in areas completely sheltered from the wind, triggering an avalanche involving this weak snow is possible. Fortunately, the low-angle meadow riding improves each time it snows and can offer a good alternative to steeper slopes today.

 

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