Bollettino valanghe

West Slopes South

Northwest Avalanche Center
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Pericolo valanghe

Wed
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 2 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

The potential for wet avalanches on sun-exposed slopes should increase on Tuesday. On shaded aspects, be leery of wind-loaded features where you could trigger a dry slide. Most avalanche activity, dry or wet, loose or slab, should be confined to this past weekend’s storm snow. 

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    Freezing levels are expected to rise and the sun will be out. With fresh dry snow already in place from last weekend’s storm, anticipate wet loose activity to spike. This process started on Monday with snow shedding from trees and rocks. On Tuesday, instead of dribs and drabs, we may be dealing with actual avalanches. These slides often start at a point before fanning out as they move downhill. If you see new rollerballs, fresh avalanche debris, or the surface is wet and sticky, head for shaded aspects keeping aware of slopes above you.

    (12/9/2024)

    Rollerballs coming out of rocky terrain on a sun-exposed slope. These are often precursors to wet avalanches.

    Photo: Dallas Glass

  • Wind Slabs

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

    The recent storm snow could still produce slab avalanches on the shaded half of the dial, particularly in wind-affected terrain. Slabs will likely be larger and potentially more sensitive as you ascend in elevation or on convex, unsupported slopes. Using uptrack tests or small test slopes to look for cracking or failing blocks of snow can give you an indication of slab potential. Visual clues such as large drifts, fresh cornices, or textured surfaces near ridgelines or rocky outcrops can help you identify wind-loaded features to avoid. 

    (12/9/2024)

    A D1.5 slab avalanche in the White Pass backcountry failed when a chunk of snow fell over a rock band. It occurred within this past weekend's new snow. 

    [E 6500' Second Bowl; SS-N-R1-D1.5-I]

    Photo: Dallas Glass

Avalanche Discussion

Observations from the West South zone on Monday indicate that this past weekend’s storm snow is settling well, but still capable of producing avalanches. Two natural slab avalanches were reported in the White Pass backcountry on Monday morning. At Paradise and Crystal, reports indicate that the sunshine kicked off some rollerballs and snow shedding from trees and rocks, but no actual wet slides. That could change on Tuesday with higher freezing levels and more morning sun.

This past weekend started wet, delivering rain to most mountain peaks before cooling down. Sunday, roughly 1-1.5 feet of snow fell on the volcanoes and just under a foot along the crest, creating the 12/7 interface. A moderate bond has been reported at this melt-freeze crust in most investigated locations. NWAC forecasters report that compared to Sunday, the previously low-density snow started to “slab up” a bit on Monday. The other story from this past weekend’s storm was the wind - with gusts well over 100 mph recorded at Camp Muir for several hours.

Our snowpack is off to a good start this year, but early-season hazards still exist. Last week’s warm and sunny weather helped diminish snow depth on southerly aspects and at low elevations. The next several days could do the same. Keep an eye out for shallowly buried or exposed rocks, creeks, holes, and logs.

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