Bollettino valanghe

West Slopes South

Northwest Avalanche Center
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Pericolo valanghe

Fri
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
3 · Marcato
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Non aggiornato — questo bollettino è scaduto 3 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

The storm train keeps rolling and should maintain dangerous conditions. With a myriad of overlapping avalanche concerns, take a step back and seek out simple terrain. Every steep open slope should be suspect no matter it’s aspect or elevation.

Problemi valanghivi

  • Storm Slabs

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

    Sure, the new snow should be healing, but with more snow on the way, slides failing as deep as the 1/16 interface could easily be 1-2ft thick. Before this storm weak facets and surface hoar were reported, along with variable surfaces and irregular wind features. This could make determining how any particular slope will react much more difficult. You’re most likely to trigger a storm slab on convex rollovers, in wind-drifted areas, on unsupported terrain, and where the slope overlays facets/surface hoar. 

    Hand pits, uptrack tests, and small slopes can all help you see how the snow may react. However, since those persistent grains may be hiding under the storm slab, if you’re going to travel on steeper slopes, look for places with lower consequence runouts.

    (1/6/2024)

    Example: Opening in the forest like this are suspect given the potential for facets and surface hoard at the base of the new snow. 

    Photo: Andy Harrington

  • Deep Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–3

    Wednesday’s stormy weather severely limited visibility and any new information about the Deep Persistent Slabs. Rest assured, the fluffy powder didn’t magically cure it. Since January 6th, a near-constant stream of very large natural and triggered avalanches have been reported. They’ve occurred in every corner of the zone.

    The question isn’t, “is the structure there?” It is. Instead, the question is, “Will it fail, right here, right now?” That’s a tough bet to take when we’re talking about D3 (very large slides) 3-6ft deep that could wrap terrain features. 

    Storm slabs, cornice falls, or finding the wrong spot could all result in big, unsurvivable avalanches. Talk about these consequences before spending time in any part (startzone, track, or runout) of avalanche terrain.

    (1/16/2024)

    Here you can see just a sampling of the recent persistent slab avalanches in the West South zone over the past 11 days. 

    Photo: Dallas Glass

Avalanche Discussion

This stormy period isn’t over. We could see a bit of a lull Wednesday night, but more snow is on the way. The mountains could receive another 6-12 inches by Thursday afternoon. That would bring storm totals to 10-24+inches for the zone. 

The stormy weather limited observations on Wednesday. Avalanche professionals in and around Crystal Mt reported a few inches of new snow, but issues were generally isolated to wind-loaded slopes, even well below ridgeline. Near White Pass, a few natural storm slabs occurred along road cuts at lower elevations on Hwy12. On the volcanoes, over a foot of snow fell, but access and weather limited information. 

You could summarize the snowpack into three concerns: 1). Failures in the new snow, 2). The 1/16 interface, and 3). The Solstice Matrx, about 4-5ft (120-150cm) below the surface. Large angular facets still linger within this crust complex. (see photos).

Regioni coperte