Bulletin d’avalanche

Salt River and Wyoming Ranges

Bridger-Teton Avalanche Center
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Danger d’avalanche

Fri
Alpin
1 · Faible
Limite forestière
1 · Faible
Sous la limite
Sans niveau
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Périmé — ce bulletin a expiré 3 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Large avalanches are unlikely. The highest chance of triggering large slides is on shady or wind-affected slopes, where weak snow exists near the base of the snowpack. Watch for recently-formed wind drifts, and due to warm temperatures, be on the lookout for loose snow avalanches on sunny slopes in steep terrain at all elevations.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely
    Taille
    1–2

    Triggering a persistent slab avalanche is unlikely but not impossible. Weak snow exists in the bottom and middle of the snowpack (~1-3 feet deep) on slopes on the north half of the compass. Know that they are likely to be under your feet or sled. Warm and dry conditions last week gave these weak layers time to rest, but they did not magically disappear.

    You are most likely to find trouble on steep, rocky, and wind-affected features.  Because these weak layers range in depth with how deeply they're buried on many slopes, slides failing on them could be large and destructive. Also, remember that tracks on a slope do not equal stability, and you may find a weak spot even after multiple people have ridden the same slope. Size up the slope before you ride it, and consider what would happen if you triggered a small slab. Would it drag you through shallow rocks or into a terrain trap?  Continue to trench your sled track or dig into the snow to see if the weak structure exists where you are riding. 

    ADDITIONAL DISCUSSION:Frank and Fitz found a recent sizable avalanche of winded snow while riding near Sheep Pass (see photos attached). Though isolated, these slabs could still be sensitive to your weight. Yesterday, I noted some small natural, loose snow avalanches on SE-S aspects. Today's continued calm and inverted weather could produce another round of similar activity on rocky, E-S-W facing slopes. Consider the consequences of being caught in a small slide before committing to serious terrain. 

     

    This wind slab failed on a melt-freeze crust on an east aspect. It seems likely that it was triggered by snowmobiles given the age of the tracks and debris combined with the refilled snow.

    Photo: Frank Carus

Avalanche Discussion

Little recent avalanche activity has been noted in the Greys Zone for the past two weeks, however found unstable snow in the neighboring Big Holes on a NE aspect around 8,400 feet. This area was shallow and lacked a thick slab of snow capable of producing an avalanche currently, in this one location. The green LOW rating does not automatically mean "send it and don't worry about avalanches." The steep, alpine terrain in the Salts poses a significant risk of a larger avalanche due to more snow. In contrast, the Wyoming Range (where you can get to the snow) could hold the highest odds of triggering an avalanche due to a shallower snowpack in spots and overall variability.  Remember: the danger rating and avalanche forecast are meant to give you baseline information to use in your travels, but YOU get to decide whether riding the terrain is a good idea. 

  • Read the forecast to understand where there are still avalanche concerns. LOW danger is "Watching for unstable snow on isolated terrain features." So continue to do just that! 
  • Make plans that clearly define terrain that is "off-limits". Stick to your plan, and have an alternate if conditions are different than you expect.
  • Evaluate terrain carefully, and never stop paying attention to consequences. If you're considering riding a slope where triggering a slide would likely be fatal and push you into the numerous exposed hazards currently (rocks, stumps) OR small terrain features terminating in a creek or flat terrain that could result in a deep burial, you need to be very, very confident in the snowpack stability. 
  • Continue to use safe travel practices. If there's any question, choose lower consequence terrain. And remember, other people are hazards, too. LOW danger usually equals MORE people in avalanche terrain, generally using less caution. 

Régions couvertes