Boletín de aludes

Salt River and Wyoming Ranges

Bridger-Teton Avalanche Center
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Peligro de aludes

Sat
Alta montaña
4 · Fuerte
Límite del bosque
3 · Notable
Bajo el límite
3 · Notable
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Desactualizado: este boletín caducó 3 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Rapid loading of snow with strong wind the last two days continuing today will create dangerous avalanche conditions. Avoid upper elevations below steep complex terrain where natural avalanche danger will be high. Assess the new snow instability carefully across all elevations and choose lower angle slopes to avoid triggering a large avalanche. 

Problemas de aludes

  • Deep Persistent Slabs

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

    Weak snow formed during a prolonged drought in December created weak layers buried near the base of the snowpack. Triggering an avalanche on these layers is most likely in areas with a shallower snowpack, such as the Wyoming Range, where the overlying slab is thin and riders can impact the weak layer. Recent snow has added stress to these weak layers. Watch out for heavily wind affected terrain that is steep, convex, or rocky. 

    In the Snake and Salt River Ranges, triggering an avalanche on these layers is more unlikely since they are buried more than 4 feet deep. Large avalanches involving new snow and persistent weak layers could step down to these deeper layers in steep and sustained terrain across the whole forecast zone. 

    (2/12/2024)

    Two avalanches pictured off Prospect Peak. The avalanche on the left had impressive propagation. Both likely failed on old snow buried Jan 4th. 

    Photo: Alex Drinkard

  • Wind Slabs

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

    Another 8 inches of snow fell overnight accompanied by W/SW winds 20-30mph. Triggering 2-3 foot soft storm/wind slab avalanches today will be likely both in sheltered and wind affected terrain across all elevations. Human triggered avalanches are more likely in upper to middle elevations near ridgelines and open/exposed terrain where wind is rapidly loading new snow. Avoid upper elevation runout zones in extreme terrain. Look for obvious signs of instability such as cracking snow surfaces.

    Easily triggered wind/storm slab avalanches failing on steep NE aspects in the Snake River Range

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1.5–2.5

    Recent snow will add stress to weak layers buried Feb 2nd overlying hard slabs 3-4 feet deep. Sensitivity of these weak layers has been most reactive on N to E aspects in the upper elevations. Avoid these areas in steep terrain as the snowpack is rapidly loaded today. Use caution in the highlighted areas of the compass rose above due to uncertainty in the distribution and reactivity of these weak layers.

     

    (2/12/2024)

    Avalanche near Blind Bull 9100' N aspect steep 37deg slopes

    Photo: Alex Drinkard

Avalanche Discussion

Don't get caught off guard, conditions are touchy.

Yesterday there was a reported natural avalanche cycle within the new storm snow that occured in the Snake River Canyon in the middle to upper elevations. The Greys zone has received around 24” of snow with almost 2” of snow water equivalent over the last two days. The characteristics each day have been significantly different. Low density snow around 5% accompanied the first pulse. Then temperatures and wind increased creating dense, firmer snow. And today you’ll find new snow slightly less dense (hopefully). There is a lot of uncertainty in trying to predict how exactly all these interfaces between storms will behave. The bottom line is we’re getting a lot of snow rapidly. A serious red flag. Especially in combination with consistently strong winds. Avoid runout zones beneath steep terrain in the alpine due to natural avalanche potential. Assess the new snow very thoroughly or simply stick to lower angle slopes to stay safe in the backcountry today. Managing the wind and storm slab instability by choosing lower angle terrain will also help manage the uncertainty of the persistent slab problems.

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