Boletín de aludes

Salt River and Wyoming Ranges

Bridger-Teton Avalanche Center
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Peligro de aludes

Thu
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 2 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Look for increasing wind speeds and drifting snow today. Wind slabs will grow large enough to be dangerous and may crack and fail under your weight.  Evaluate terrain and weather carefully, especially in the afternoon, and watch for signs of wind-drifting. While unlikely, riders could also trigger a large avalanche that fails on weak snow buried near the ground where the snowpack remains thin.  The danger is highest in steep, rocky, and wind-affected terrain.

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–2

    Newly developed wind slabs one to two feet thick are likely to become sensitive to triggering due to a notable increase in wind speeds today. This zone has received 8-12" of snow since last Friday with relatively light winds since that time. Today, wind will increase significantly and shift towards the southwest, accessing and moving snow on the ground and new snow from the forecasted snow showers. Watch out for signs of wind loading like fresh cornices, plumes at the ridgetop of textured surfaces. Hollow sounding, upside-down snow, and shooting cracks are strong signs that you could trigger an avalanche. Seek out sheltered terrain to avoid this problem.

    Shooting cracks like this are a clear sign that wind slabs are present and could be triggered.

  • Deep Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Unlikely
    Tamaño
    2–3

    Weak snow that formed in December persists at the base of the snowpack across the entire Greys River forecast zone. However, the thickness of the hard slabs that overlay this weak snow varies based on geographic location. In the middle and upper elevations of the Salt, Snake River, and deeper portions of the Wyoming Range, these weak layers are buried 3-5+ feet deep making it unlikely for a human to impact them. In shallow parts of the forecast zone, such as the far eastern side of the Wyoming Range, these slabs are only 2-3 feet thick making it more possible for humans to trigger avalanches on the buried weak layers. Shallow, rocky, and unsupported terrain on the north half of the compass is where you are most likely to impact weak layers. Keep in mind that a large trigger such as a cornice fall could trigger one of these very large avalanches, even in areas where the snowpack is deep.

    Identify thin areas in the Greys River zone as you ride. Probing or digging can provide useful information about the depth of the weak layers preserved at the bottom of the snowpack. This evaluation is critical if you are riding in a shallow part of the zone. A total snow depth of less than 5 feet (150cm) is a red flag.

    The last reported human-triggered avalanche involving deeply buried weak layers occurred on March 9th on the far eastern side of the Wyoming Range.

    (3/9/2024)

    The last reported human triggered persistent slab avalanche occurred on the far eastern side of the Wyoming Range.

Avalanche Discussion

New snow that has fallen since Friday has been mostly stable with only a few thin wind slabs reported in extremely steep, high elevation terrain. At upper elevations, the new snow has been deep enough  to run in dry, loose avalanches which required some management on northerly terrain. Compounding matters has been the crust that exists beneath the new snow. You'll find it under your track up to 9,000' on most northerly slopes, higher on southerly aspects, due to recent warming. The front approaching today may whip up new snow and a wind slab avalanche problem along with it that could be problematic in steep, wind loaded terrain. 

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