Bollettino valanghe

West Slopes South

Northwest Avalanche Center
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Pericolo valanghe

Tue
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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In sintesi

Give the snowpack some time to adjust to the rapid change it just underwent. If you’re sinking into wet snow past your ankle, start thinking about wet avalanches on slopes over 35 degrees. If you are at upper elevations, be mindful of slides occurring in the recent storm snow, especially on the volcanoes.

Problemi valanghivi

  • Storm Slabs

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

    Above the rain/snow line, expect the possibility of Storm Slabs. Observations from upper elevations are extremely limited, but the snow likely came in heavy and wet, creating an upside-down snowpack. Before committing to a slope, you’ll need to dig down to the 12/6 interface and check all of the recent storm snow for instabilities or heavy snow over weak snow. These avalanches will be more likely in wind-loaded terrain or on steep features over 35 degrees. 

    A small skier triggered slab avalanche in steep rocky terrain from this past weekend.

    Photo: Shane Robinson

  • Loose Wet

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

    Wet avalanches can occur long after the rain has stopped, making them difficult to predict. You could encounter a range of wet problems on slopes over 35 degrees anywhere you’re plunging into moist snow past your ankle. The most likely issue you’ll face should be loose avalanches. These slides often start at a point and fan out as they move downhill. In some instances, they could even trigger slabs as they descend. 

    Numerous loose avalanches initiating out of steep rocky terrain in Silver Basin on 12/10.

    Photo: Katherine Baals

Avalanche Discussion

Skies will gradually clear on Monday as we distance ourselves from the rainy weather that again soaked the majority of our snowpack and brought with it a variety of avalanche concerns over the weekend.

Observations from much of the zone are non-existent, but we do have some information from the Crystal Mountain backcountry. Professionals and recreationalists alike noted natural wet avalanche activity coming out of steep slopes near ridgelines. Additionally, after ascending through wet snow up to 5000’, the surface transitioned to a breakable crust. We expect cooling to help develop more widespread surface crusts in open areas.

Most NWAC weather stations rose above freezing during this event, but you could find that upper elevations on the volcanoes are holding significant snow totals. Paradise recorded over 4” of water in a 24-hour period from Saturday night into Sunday. Prior to the rain, multiple natural and skier-triggered avalanches were reported on Saturday in the new snow. We do not anticipate any avalanches below the 12/6 interface on Monday. 

Current travel conditions in the mountains requires your focus. Creeks are swollen, holes are open, and rocks/bushes are either shallowly buried or poking through our thin snowpack. Don't let one of these early-season hazards catch you off guard.

Regioni coperte