Bollettino valanghe

West Slopes South

Northwest Avalanche Center
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Pericolo valanghe

Thu
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto last year. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

A few inches of new snow could make it harder to spot potentially wind-loaded slopes. Rime on trees, sharp cornices, and larger drifts can help you decipher local wind patterns and anticipate potential slabs. These avalanches may trigger on very steep terrain, unsupported slopes, or convex rollovers.

Problemi valanghivi

  • Wind Slabs

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

    Wind slabs were common in the West South on Tuesday. While the mild weather should help them heal quicker, they won’t magically disappear. Unfortunately, potential avalanches may be hiding under a few inches of fresh snow. You’ll need to keep a keen eye open for signs of wind transported snow and pay attention to how conditions feel beneath you. 

    You’re most likely to find wind slabs along exposed ridges, below cliffs, in the tops of chutes, and at upper elevations. Some slabs could be more than 12-18 inches thick and fairly firm. 

    Give firm wind loaded slopes a wide berth, especially in higher consequence terrain. Despite their smaller size, avalanches on Tuesday ran the entire length of the slopes on a strong crust.

    (4/1/2025)

    Clear signs of wind transported snow were common along ridges. They help identify local wind patterns and anticipate possible wind slabs.

    Photo: Dallas Glass

  • Loose Wet

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

    You can think of this problem as “if-then.” IF the sun comes out, THEN expect the new snow to slide downhill. 

    It’s April, it doesn’t take much for the sun to wield its power. Even some filtered sunshine or a short sun break could set the wet loose problem in motion. We’re expecting both on Wednesday. If you start to notice the sun, so is the snowpack. 

    You may trigger small wet loose slides or natural avalanches could release on very steep and rocky slopes. Similar to the wind slabs, once te snow gets rolling it may travel a long way on the underlying crust.

    (4/1/2025)

    This avalanche started as a very small wind slab, but then entrained snow more like a wet loose. It ran for more than 300 vertical feet and buried a recent ski track. NNE, 6300ft, WL-ASc-D1-R1-S

    Photo: Dallas Glass

Avalanche Discussion

Wednesday could run the whole gamut of spring weather. Clouds, showers, sun, breeze, calm, cold, and warm… all in one day. Sounds about right for April. Snow accumulation looks minimal, winds generally light, and sun breaks short lived. So, no one weather factor is really driving the forecast. If one dominates where you are, you’ll need to adapt accordingly. 

Wind slabs were reported Tuesday from Mt Saint Helens, White Pass, and Crystal Mountain areas. While they were a bit stubborn, they were easy to find, many slopes produced large cracks, and a few test slopes fully failed. Similarly, some filtered sunshine helped make wet loose slides possible. Even though they were tough to get going, once moving, they ran easily. We joked that some of these avalanches blurred the lines between boxes as ‘wet-wind loose-slabs.’ 

Below the recent snow, the March Atmospheric River (AR) crust has become stronger and stronger at middle and upper elevations. It should help all but eliminate the chance for a wet shed-style avalanche for the moment. 

At lower elevations, the snowpack has taken a beating. Expect patches of bare ground, open creeks, and plenty of tree debris.

Regioni coperte