Bollettino valanghe

Salt River and Wyoming Ranges

Bridger-Teton Avalanche Center
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Pericolo valanghe

Fri
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
Senza grado
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Non aggiornato — questo bollettino è scaduto 3 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Weak layers buried below a firm cohesive slab will create continued dangerous avalanche conditions. Remote triggering of avalanches from above, below, or to the side of steep slopes have occurred over the last week and will be possible today. Intentional route-finding to identify and avoid steep slopes will be necessary for safe backcountry travel.

Problemi valanghivi

  • Persistent Slabs

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

    Numerous avalanches have been reported since our last storm indicating that buried weak layers are still reactive and adjusting to the snowpack. Slab depths above these weak layers are 1-2 deep with locally higher amounts in upper elevations on previously wind loaded terrain. You will most likely find this problem on slopes facing NE-N-NW above about 8,500’. On these aspects and elevations, preserved snow from early fall has created a weak snowpack structure that is sensitive to remote triggering. Analyze the terrain you travel in carefully to avoid being caught off guard by the unpredictable nature of this type of problem. Look for any cracking and collapsing as these are obvious signs of instability. 

    This observation above Triple Direct is a good example of an avalanche being remotely triggered.

    (12/5/2023)

    This photo accurately depicts the current persisent slab problem and remote triggering from gentle terrian above, below, or to the side of steep slopes.

    Photo: Travis Baldwin

Avalanche Discussion

A series of large natural and human triggered avalanches have occurred on buried weak layers since Dec 2nd discussed above. These weak layers continue to trend unstable. In other words they are guilty until proven innocent. Little to no snow existed above 8500’ before our last storm Dec 1st. So the primary concern is where old preserved snow from Nov/Oct lies beneath a cohesive slab that has stiffened the last several days with warm temperatures. The weak snow interface we are talking about has behaved in unpredictable ways with remote triggers reported. Expected snowfall today of 4-7” with moderate SW winds could add stress to these buried weak layers and increase reactivity by this afternoon. This new snow will fall on crusts on southerly aspects and weak facets on upper elevation shaded aspects. Monitor snowfall amounts today as avalanche conditions could heighten throughout the day and into tomorrow where small slabs form on leeward terrain (N-NE-E-SE) in middle and upper elevations. 

Regioni coperte