Bulletin d’avalanche

Salt River and Wyoming Ranges

Bridger-Teton Avalanche Center
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Danger d’avalanche

Fri
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 2 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

A combination of strong wind, recent snow, and a weak snowpack will see continued dangerous avalanche conditions today. Wind speed increased yesterday and last night gusting 70-90 mph forming fresh wind slabs where triggering an avalanche on steep, wind loaded terrain is likely. Steer clear of wind loaded terrain and look for signs such as large pillows and drifts with rippled or cracking snow surfaces.

Problèmes avalancheux

  • Wind Slabs

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

    This week the forecast area received 22-26” of snow with over 2” of SWE in the middle and upper elevations. All this snow combined with sustained west/southwest wind over 40 mph has created wind drifted soft slabs over 3’ deep on exposed leeward terrain. Avalanches triggered on wind loaded terrain could be large and travel far cross-slope as these stiff wind slabs lie above persistent weak layers. Triggering an avalanche remotely is possible from gentle slopes above, below, or to the side of steep slopes. Steer clear of wind loaded terrain today by using cautious route finding above 7500’.

    (12/18/2024)

    Increased wind loading yesterday combined with a poor bonding layer will make triggering avalanches likely along ridgelines such as this today.  

  • Persistent Slabs

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

    Weak layers are buried beneath 1-2’ soft slabs. These weak layers are persistent meaning that you can continue to trigger avalanches on steep terrain sheltered from the wind even without any additional snowfall. This problem is widespread across all aspects in the middle-upper elevations and most dangerous on wind loaded terrain as mentioned above. Remotely triggered avalanches are possible. Evaluate terrain carefully where even a small avalanche could have serious consequences such as terrain traps into creeks, gullies, or trees.

    (12/15/2024)

    Remotely-triggered soft slabs failing on persistent weak layers on terrain sheltered by the wind. 

    Photo: Bridger-Teton Avalanche Center

Avalanche Discussion

Today we are transitioning avalanche problems from storm slabs to persistent slabs. Multiple storms this week have buried weak layers that were formed early December during dry weather. We have transitioned to a persistent slab problem because weak layers of sugary facets will continue to be reactive to human triggered avalanches without significant snowfall or wind. The caveat is that we received significant wind loading yesterday so specific terrain may be more reactive than yesterday. You can drastically reduce your chances of triggering a large avalanche by avoiding wind loaded terrain. Remember that early season snowpacks are tricky to understand and demand respect. Low avalanche danger exists in the lower elevations as most slopes were bare of snow before the recent snow and lack persistent weak layers. 

The good news is we received a significant amount of snow this week making backcountry travel more accessible across many areas of the Salt River and Wyoming ranges. Be aware that the snowpack is still thin however, and hazardous obstacles are lying just below the snow surfaces. It’s a long season ahead, caution is advised with thin snow coverage and dangerous avalanche conditions.

Régions couvertes