Bollettino valanghe

Salt River and Wyoming Ranges

Bridger-Teton Avalanche Center
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Pericolo valanghe

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

In sintesi

Triggering an avalanche is possible in steep, wind loaded terrain at the upper elevations. Additionally, small wet loose avalanches are possible on sunny aspects as the day warms. Deeply buried weak layers persist in the snowpack and are most likely to be impacted in the shallowest portions of the forecast zone, or by large triggers such as cornice falls. Keep an eye on warming today, give cornices a wide margin, and carefully assess steep terrain before traveling on it or under it.

Problemi valanghivi

  • Wind Slabs

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

    Wind slabs with depths up to 2 feet are still lingering in steep, wind loaded terrain at the upper elevations. These slabs have become less sensitive to human triggers over the past few days, however, triggering one of these slabs may still be possible on very steep slopes. Obvious signs of instability such as cracking or collapsing may not be present as you approach a wind loaded slope. Watch for stiff wind affected snow that may feel “punchy” if you probe or dig. Wind slabs will become more reactive during the heat of the day.

    Cornice Falls: Warm temperatures and sunshine today will increase the potential for cornice falls. Give cornices a wide margin and be careful along ridgelines as they can break further back than expected. Limit exposure under cornices, particularly in the afternoon. Cornice falls are the most likely way to trigger a very large persistent slab avalanche. Check out this observation highlighting recent Cornice Falls.

    (3/8/2024)

    Evidence of cornice fall triggering an avalanche near Sheep Pass.

  • Loose Wet

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

    Mostly sunny skies and warm temperatures will decreasestability on sunlit aspects by the afternoon. Watch for snow surfaces to become wet and easier to penetrate as a sign of wet looseavalanche potential. These avalanches will be small but could knock you off your feet or machine in steep terrain. The snow around rocks and cliffs will warm up earlier in the day resulting in more activity. Upper elevation wet loose activity will be isolated to southerly aspects that are steep and rocky.

    Wet loose avalanche often fail near rock outcropings. In this image, the cliffs have heated up and impacted snow surfaces. Watch for this hazard today.

    Photo: Gabrielle Antonioli

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–3

    Persistent slab avalanches continue to be most likely triggered in areas where the snowpack is thinnest; steep, rocky and wind affected terrain should be suspect. These layers often struggle with big weather events. The recent snow and wind added a lot of weight to the buried weak layers and today’s warming should raise concerns. This time of year we generally see persistent weak layers become more stable, however this is a slow process and large, destructive avalanches on these layers continue to be a possibility. Weak snow that formed in December is buried 3-5+ feet beneath a firm slab at middle and upper elevations in the Salt, Snake River, and deeper portions of the Wyoming Range. In these deep areas, it is unlikely that a human will impact the buried weak layers. Persistent weak layers are closer to the surface, making them more suceptible to triggering, in the drier parts of this forecast zone and at lower elevations.

    (3/9/2024)

    A large persistent slab avalanche that occurred in a shallow part of the Wyoming Range.

Avalanche Discussion

As we transition towards spring, it’s important to remember that avalanche hazard this time of year is often dictated by daytime heating. Today is a taste of what is to come. Any lingering wind slabs at the upper elevations will become more sensitive as the day warms and the sun becomes more intense. Loose sluffs will begin around midday in steep, sunny terrain and may grow larger in the afternoon. Furthermore, cornices will have the greatest chance of failing, potentially triggering a very large persistent slab avalanche, during the heat of the day. All of this is to say that the avalanche hazard today will be at its peak during the afternoon. Fortunately, you can mitigate your exposure to these hazards with some simple tactics.

  • Carefully assess steep wind loaded terrain, especially in the afternoon.
  • Get an early start. 
  • Move to shaded slopes if surfaces become wet.
  • Give cornices a wide margin. Don’t linger underneath heavily corniced ridgelines.

 

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