Boletín de aludes

East Slopes Central

Northwest Avalanche Center
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Peligro de aludes

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

Lo esencial

A wet and warming storm is expected to create dangerous conditions on Sunday. Wet avalanches of all types could run from steep slopes, and could become large by the afternoon. Stay off steep slopes by the time the surface crust breaks down, or if new snow is gloppy, wet and entrains into wet loose avalanches.

Problemas de aludes

  • Loose Wet

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

    Wet snow avalanches of all types could begin to run naturally on Sunday. A few to several inches of new snow may accumulate before temperatures warm up Sunday afternoon, especially near the crest. As snow turns over to rain at all but the highest elevations, expect fairly widespread instabilities. Heavy, wet loose slides could churn downhill on long steep slopes. Slides could begin to gouge deeper into the snowpack as rain continues to weaken old layers. Rollerballs and fresh chunky avalanches will be good indicators of the dangerous conditions. Wet slabs and storm slabs could also run from the higher elevations, and entrain wet snow on their way down to become large slides.

    With all of the above, the travel advice is clear- stay off of steep slopes if you find more than a few inches of newer snow that has become saturated, or is deep and heavy. Stay out from underneath large steep slopes as slides could make long runouts into gullys. 

    (4/7/2023) Example loose wet avalanches from Snoqualmie on Friday. Patrick O'Moore

Avalanche Discussion

We're about to get drenched as the warm and wet storms continue Saturday night through Monday. Snowpack depths have held fairly steady, but im guessing we'll start to see them decrease on Sunday, especially at and below 5,500ft. The snowpack at lower elevations is well on its way to melting out for the year, but higher up it's deeper and drier. Most aspects hold a crust of sorts beneath the recent storm layer. As snow changes to rain and precipitation rates increase during the afternoon, expect increasing danger. A natural avalanche cycle could occur overnight into Monday, and may continue during the day. 

The first wave of these storms left the zone with 4-10" of new, dense snow and over an inch of water equialent for some areas like Mission Ridge and Leavenworth. Snow levels fluctuated, but in general snow accumulated above 5,000ft. Higher elevations saw light rain for a time. Observers were able to trigger small, loose wet avalanches below about 5,800ft at Mission Ridge on Friday. On Saturday, Mission Ridge Ski Patrol reported sensitive large cornices, and some of these triggered slabs that stepped down to a layer of buried surface hoar from late March (see photos below).

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