Bulletin d’avalanche

West Slopes South

Northwest Avalanche Center
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Danger d’avalanche

Tue
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 7 months ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Warming temperatures could make triggering avalanches easier as the day progresses. Keep tabs on how conditions are changing and be ready to avoid steeper slopes if slides become more common or larger.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    If you find yourself traveling on colder and drier snow, then focus on the chance for slab avalanches. How will these warming temperatures affect these potential slides? It's always hard to say, but it could turn the snow more upside down and make them easier to trigger. You may see small, shallow slabs failing on just about any steep slope, but it’s the wind loaded terrain where the real danger lies. 

    Look for rime, drifts, and cornices to point towards potential wind slabs. You can try using small slopes to see if these slabs crack or fail, but it may be hard to fully assess them while conditions are so dynamic. Instead, look for wind stripped or lower angled slopes to work around likely loaded areas. 

    In locations that recieved more snow, like Mt Saint Helens, Mt Rainier, and White Pass, these avalanches could be big enough to kill you on their own. In other spots, expect very thin, small slabs.

    (4/1/2025)

    Example: 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

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–1.5

    Near and just above the rain-snow line, there’s already wet snow you can push into a loose avalanche. However, as temperatures rise and rain reaches higher up the hillside, these slides could become easier to trigger. Down low and in drier areas of the zone, there’s probably not enough new snow to pose a real hazard. But, through most of the area, at middle elevations,  there could be 6-8 inches of snow for an avalanche. 

    Even if this problem is likely, these slides should stay small. So, think about the consequences of the terrain before committing to a slope. Wet avalanches can easily carry you over cliffs, through trees, or into a creek. 

    While we’re mostly worried about the recent snow since Sunday, in a few isolated slopes, slides could entrain additional wet snow that fell last week, allowing them to grow bigger. This would be most likely on long sustained steep slopes at middle elevations.

    (1/31/2026)

    These rollerballs highlight the wet loose hazard from the past few days. 

    Photo: Dallas Glass

Avalanche Discussion

Since last Wednesday, the West South has seen a series of storms with fluctuating snowlevels. How much snow fell depends a lot on location and elevation. Water totals range from 1.5 inches near the crest to 3-4 inches on the volcanoes. At middle elevations, this resulted in 8-18 inches of snow, but it's probably much deeper higher in the terrain. Sunday’s snow likely fell on a thin new breakable crust (the 2/1 interface). Not surprisingly, most of the upper snowpack alternates between moist new snow and thin crusts. Below all these storms is a more prominent, thick, and solid crust (January Drought Interface). There aren’t any concerns below this layer. 

While the return to winterish weather has been nice, conditions remain painfully thin. Wet heavy snow, breakable crusts, patches of ice, bare ground, and a seemingly endless parade of obstacles take time and patience to navigate safely.

Régions couvertes