Bollettino valanghe

West Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

Sun
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 7 months ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Expect a wet and windy day in the Central Cascades. Avoid traveling beneath cornices, glide cracks, and slopes showing signs of recent wet avalanche activity. At upper elevations, steer clear of steep slopes with freshly wind-drifted snow. Stormy conditions will likely limit travel into higher terrain on Saturday.

Problemi valanghivi

  • Wind Slabs

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

    Heavy snowfall and strong winds through the day should form fresh slabs. The slabs of moist new snow will probably be stubborn to trigger, but with stormy conditions and bad visibility, they won’t be something you want to mess with in steep, upper elevation terrain. If snow levels are lower than forecast, wind slabs could also start forming at mid elevations.

    Blowing and drifting snow should show you which slopes are loading up if you do make it up high. Cornices and scoured slopes can help you identify wind-loaded terrain after the wind stops blowing. You are most likely to trigger a wind slab during or immediately after its formation.

    (3/12/2022)

    Blowing snow is the most obvious sign that wind slabs could be forming on leeward slopes.

  • Glide Cracks

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

    The biggest concern on Saturday is probably not widespread wet loose avalanche activity, but an isolated, high-consequence release of a cornice, glide slab, or block of snow shedding from a cliff. Even a small chunk of snow falling from above can entrain saturated snow on the slope below, and turn into a decent-sized avalanche by the time it hits the runout.

    Many low-elevation areas have thin, patchy snow cover, but if you’re traveling on snow at low elevations, use the same caution you would at mid elevations. Identify overhead hazards and limit your time beneath them. If you make it just above the rain–snow line, you may also see fresh rollerballs and trigger small amounts of wet new snow on steep slopes.

    (12/21/2023)

    A thin and wet snowpack is breaking and gliding on this steep, vegetated surface in the Baker backcountry.  

    Photo: Andy Harrington

Avalanche Discussion

It’s been a quiet week in the Cascades. At Stevens Pass, there is a 2–4 inch thick surface crust and no signs of recent wet avalanches in or near the ski area over the past three days. At Snoqualmie Pass, observers have found firm snow surfaces, with southerly aspects softening during the day, and no reported avalanches. The snowpack is also getting quite thin, and typically snow-covered, frozen lakes are slushing up. Observers in West North noted that Tuesday was the last day with notable avalanche activity.

It might seem ironic to say that 5000’ temperatures cooled to the upper 40s and low 50s on Friday, but that’s the case after highs over 60 degrees on Thursday. Observations have been limited in recent days as many users appear to have shifted away from snowy mountain travel. Fewer reports likely reflect fewer people in the mountains, not necessarily a complete lack of recent avalanche activity.

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