Boletín de aludes

West Slopes Central

Northwest Avalanche Center
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Peligro de aludes

Sun
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
2 · Moderado
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Desactualizado: este boletín caducó 5 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Avalanche danger will increase with 11,000’ freezing levels and strong sun initiating loose wet avalanches. Avoid travel on and under steep terrain as the snow surface warms or if you observe signs of instability. Avalanche danger will be greater along Hwy 2 in areas that received more new snow.

Problemas de aludes

  • Loose Wet

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

    Loose wet avalanches in new snow were observed on Friday around Stevens Pass with the warmest days still to come this weekend. Expect to see more of these avalanches in the days ahead as freezing levels skyrocket and the sun makes a strong showing. The likelihood is higher near and above treeline where newly fallen snow will be more susceptible to warming, become weaker, and therefore more likely to avalanche. Move to lower angle terrain and away from steep slopes above when you begin to see signs of instability like rollerballs, a rapidly warming snow surface, or current avalanche activity.

    Also avoid traveling below sagging cornices, glide cracks, and large, unsupported blocks of snow clinging to rock faces. Though the danger from these will be highest on sun-warmed slopes at midday, be aware these avalanches can still release at any time.

     

     

    (1/21/2022)

    Wet loose avalanches ran on the 21st on a southerly aspect near the Wellington area at Stevens Pass.

    Photo: Brian Murphy

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–1.5

    New snow and moderate to strong winds likely created new wind slabs at upper elevations. Though small they still pose a risk to backcountry travelers in steep, exposed terrain. They could also become easier to trigger during periods of warming. Monitor new snow depth and the extent of wind transport as you ascend. Use visual cues like scoured snow surfaces and cornices to figure out where unstable winds slabs could be hiding. Identify and avoid steep features like convex rolls and other unsupported terrain with signs of recent wind loading.

     

     

     

    (1/21/2022) Wind affected snow surfaces on the north slopes of Chair Peak in Snoqualmie Pass.

    Photo:  NWAC Public Obs

Avalanche Discussion

The coming weekend will bring a combination of the strongest sun and warmest temperatures we have seen yet this year.  On the other hand, we have a very strong rain and melt affected snowpack that has been through wet avalanche cycles plus nearly two weeks of melting, draining, and freezing. This should soften the blow of rapid warming and make for generally lower avalanche danger compared to similar weather with a colder, drier snowpack.

The outlier to this are areas that saw significant new snow on Thursday such as Stevens Pass, the southern West Central along the Hwy 2 corridor, and areas in West North closer to the Cascade Crest. The latter likely experienced lower snow levels accompanying heavy precipitation. The new snow will be more reactive to warm temperatures with loose and slab avalanches larger and more likely.

Other than avalanche hazards, expect challenging travel conditions on frozen, uneven surfaces earlier in the day. Steep tree covered terrain has been noted as particularly difficult to navigate. If you haven’t made it to the mountains since the rain and warm temperature regime took over 10 days ago be prepared to see a very different environment. Exposed rock, glide cracks, open creeks and a very rough snow surface all present new hazards to avoid.

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