Bollettino valanghe

Salt River and Wyoming Ranges

Bridger-Teton Avalanche Center
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Pericolo valanghe

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

In sintesi

Recent snow accompanied by moderate winds formed slabs and buried a weak layer 2-3 feet deep that resulted in numerous avalanches. Triggering an avalanche will be possible today, especially in areas that contain a combination of lingering wind slabs above that weak layer. Careful terrain assessment will be required to identify previously wind loaded terrain and the sensitivity of the buried weak layer across different aspects. Monitor for increased reactivity on slopes that receive sun. 

A large avalanche was remotely triggered yesterday in Mosquito Creek. 

Problemi valanghivi

  • Wind Slabs

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

    Sustained W/SW winds above 20 mph two days ago formed soft wind slabs. These slabs will still be reactive today in the upper elevations. Slabs depths will be up to 2 feet deep with 3 feet possible in specific terrain. Areas with the highest likelihood of triggering will be on leeward and cross loaded exposed terrain below cliffs and confined features such as couloirs. Look for obvious signs of instability such as cracking, stiffened or ripple surfaces, and drifts.

    (3/25/2023)

    Obvious sign of unstable new snow with deep, large cracking on a wind loaded pocket. 

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2.5

    A significant amount of new snow now sits on an old, weak interface composed of facets and crusts created during drought conditions and buried March 20th. Slab depths will range 2-3 feet.  Areas that harbor facets above a stout crust will be the most reactive on W, S, and E aspects. Wind loaded terrain will also increase the potential to trigger this buried weak layer. Multiple avalanches triggered remotely were observed during peak loading (Wolf Creek, Palmer Creek). Remote triggering will be possible today but less likely as sensitivity decreases over time. 

    Deeper weak layers buried in February also pose a threat in areas with a poor snowpack structure including the Wyoming Range. Triggering an avalanche above these layers cold step down and trigger a very large avalanche. This deeper layer has trended dormant in the Salt and Snake River Ranges. 

    Low elevation avalanches will be possible on weak snow near the ground as increased temperatures and sun impacts solar aspects W-S-E. 

    (3/27/2023)

    Mosquito Creek Area remote triggered avalanche that failed on March 20th weak layer. 2-3' crown depth. D2 R3

    Photo: Will Mook

Avalanche Discussion

Persistent Slab Complexity

The big question on everyone’s mind is the weak interface buried March 20th during the recent storm cycle. This interface resulted in multiple avalanches that were sensitive to remote triggering, which is now depicted as a persistent slab problem. All avalanche activity occurred on easterly aspects where near surface facets lie above a stout crust. A high amount of uncertainty remains in regards to the sensitivity and distribution of this weak layer across different aspects. Continued cold temperatures will slow the process of stabilizing this weak layer, so understanding the consequences of triggering a large avalanche should be in the forefront of your decision making as you travel in the mountains today. Dig down and identify this layer to aid your terrain choice. 

Regioni coperte