Bollettino valanghe

Salt River and Wyoming Ranges

Bridger-Teton Avalanche Center
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Pericolo valanghe

Sun
Alta quota
2 · Moderato
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

New snow and wind have formed sensitive wind slabs up to 1 foot thick at upper elevations. Pay attention to signs of wind-loading including the formation of pillows and shooting cracks. Although far less likely, weak layers buried 2-4 feet deep remain a concern for triggering large avalanches in terrain with a weak and shallow snowpack on very steep (>35°) slopes.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–1.5

    Wind slabs averaging 1 foot thick have formed in the upper elevations after a storm brought 1 to 2 inches of new snow in the Wyoming Range and 6 to 8 inches in the Salt River Range. These slabs may be smaller in the Wyoming Range, where new snow totals are less.  Expect to find these generally small slabs on all aspects as moderate winds have shifted from the north to the east overnight. Before the most recent storm, snow surfaces weakened over the last two weeks. New wind slab formations on this surface will be sensitive and human triggers are likely.  In neighboring zones, multiple small wind slabs have failed on this weak snow demonstrating the poor structure beneath the new snow. Expect to find these slabs along ridgelines, in cross-loaded gullies, and on steep convex rollovers. Pay attention to signs of wind-loading including the formations of pillows, textured surfaces, or shooting cracks. Triggering a small wind slab can have large consequences, especially near gullies, cliff bands, and trees. Moving to terrain sheltered from the wind will help you avoid this problem. 

    (1/23/2025)

    Shooting cracks and rippled snow surfaces indicate signs of instability on wind loaded terrain. 

    Photo: Bridger-Teton Avalanche Center

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    1.5–2.5

    Weak snow is buried by hard slabs 2-4 feet deep. The odds of triggering a persistent slab avalanche have decreased over time. Unfortunately, these weak layers require a long time to heal. Although unlikely, it is not impossible to still trigger a persistent slab avalanche. Shaded, northerly slopes over 35° steep that contain thin, sensitive areas in the slab are the most likely places to impact buried weak layers. Thin spots usually exist around rocky, and wind-scoured terrain.

    Areas that contain a shallower and therefore weaker snowpack are where persistent slab avalanches are most concerning. The Wyoming Range contains shallower snow depths than the Salt River Range. Stability tests are still showing unstable results despite the lack of recent avalanches. Lower elevation terrain lacked snow during drought conditions in December when persistent weak layers formed.

    (1/13/2025)

    This photo from the Wyoming Range is an example of where you can trigger persistent weak layers. 

Avalanche Discussion

Winds have varied from W to N to E over the last 48 hours. As such, wind slabs are expected on all aspects today. The less common eastern wind today will cause wind slabs to form in unusual locations. Stay alert for signs of wind-loading throughout the day as these eastern winds will continue into the evening and overnight. 

The spatial variability of snow depths and persistent weak layers across this zone is large. The odds of triggering a persistent slab are increased on isolated terrain features where the weak layers are buried 2-3 feet deep. Areas where the persistent weak layer is buried 3-4 feet deep, such as upper elevations or many parts of the Salt River Range, will be even more unlikely. Your odds of triggering an avalanche are slowly decreasing, but each day is only incrementally safer than the last. The last reported cycle of persistent slab avalanches occurred on January 7th. The buried weak layers are slowly gaining strength. Remain vigilant when traveling through avalanche terrain in areas that contain a weak and shallow snowpack. The best way to identify these areas is to probe for snow depths or look for low snow coverage where rocks or vegetation are still showing.  Identify complex terrain where avalanches are more likely and look out for terrain traps where unsuspecting slopes can have serious consequences.

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