Bulletin d’avalanche

East Slopes North

Northwest Avalanche Center
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Danger d’avalanche

Wed
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Périmé — ce bulletin a expiré 7 months ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Continued warm temperatures will sustain dangerous wet snow avalanche conditions. You could easily trigger avalanches in heavy, wet snow on steep terrain, or it may slide unexpectedly from above. Stick to traveling on low angle terrain and don't linger beneath large snow-covered rocks or gullies where wet snow may flow from above 

Problèmes avalancheux

  • Loose Wet

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

    The rain will taper off, but temperatures will continue to rise. With cloudy skies overnight, we also don't expect much of a surface crust to form. This means the snow will remain heavy, wet, and weak. It's possible that the full menu of wet avalanche problems is on the table for Tuesday. If you're sinking deeply into wet snow, you could easily trigger wet loose avalanches on steep slopes.

    Rock slabs or cornice falls can shed large blocks of snow from overhead. Wet avalanches that initiate at higher elevations may funnel through gullies into lower elevations. With crusts and previous weak interfaces in the upper snowpack, there is even a chance for wet slab avalanches. While these are less likely, they are much more unpredictable.

    Wet snow problems come with significant uncertainty, so let the snowpack adjust to these tropical temperatures. Stack the odds in your favor by sticking to low-angle terrain and limiting time spent under rock slabs or gullies.

    (12/11/2025)

    An example of a large wet avalanche that ran during a previous atmospheric river event in December. [Harts Pass]

    Photo: Justin O’Hara

Avalanche Discussion

There is a chance of very light rain on Tuesday morning, but the trend will be toward drier and, unfortunately, warmer weather. High, thin clouds may slightly reduce solar input, but even those clouds will be on their way out by Tuesday evening. 

About .8" of rain was recorded at Washington Pass in the past 24 hours. We don't have many direct observations, but we suspect similar conditions as in other nearby zones that experienced a widespread natural wet avalanche cycle.

Over the past couple of days, observers reported avalanches and signs of instability in wind-loaded terrain that involve all (2ft) of the recent storm snow, and even breaking on the January 3rd (1/3) crust. This crust varies with aspect and elevation and is often reported to be more robust at higher elevations due to temperature inversions. Some observers have found weak layers resting over this crust. Even after the rain stops, warming can still affect these layers, creating dangerous wet-slab conditions. Wet slab activity tends to be delayed, but the timing is very hard to forecast. If they occur at all, the tipping point may be continued warming and sun on Tuesday or Wednesday.

There are a few other notable crusts in the mid and lower snowpack. But we don't expect them to be an issue for avalanches during this rain and warming event. 

Régions couvertes