Bulletin d’avalanche

Snoqualmie Pass

Northwest Avalanche Center
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Danger d’avalanche

Wed
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 8 months ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

It’s going to take some real sunshine to develop an avalanche issue on Tuesday. If it stays partly cloudy, there might not be much hazard. If you find wet sticky snow on steep sunny slopes, head to more shaded terrain where the snow is fluffier.

Problèmes avalancheux

  • Loose Wet

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

    This problem is far from a slam dunk. Instead, it’s more of an “if-then" scenario. IF the sun comes out, and IF the crust on southerly slopes breaks down, THEN you could encounter wet loose avalanches. Even above the inversion, high thin clouds might keep the sun from impacting the snow. 

    Fortunately, this is easy to monitor. The first thing you’ll notice is how much warmer it feels in the sunshine. If you feel hot, the snow probably does too. Look for new rollerballs, and snow shedding from rocks/trees. These are often the precursors for wet slides. Natural avalanches could release from rocky slopes, and you might trigger one in steep sunny terrain. Keep your eyes on what’s above you. Some slopes may be basking in the sun while you shiver in the shade. 

    At lower elevations, low clouds and colder temperatures should keep this from being an issue. These inversions and clouds might even keep the middle elevations locked up all day. West of the Pass, things could be a different story, with loose wet avalanches at all elevations.

    (12/29/2025) These rollerballs and wet loose likely released on Sunday during the initial sunny spell. Photo: Carl Marrs

Avalanche Discussion

The Pass sits right at the collision of cold air in the Columbia River Basin and the warmer air moving in under the high pressure ridge. This could result in some wild temperature and cloud differences east to west and with elevation. A strong temperature inversion is expected near and east of the pass, along with the chance for low clouds and fog. It's hard to say how high these chillier temperatures will reach. However, somewhere up there it's warm. West of the Pass proper, there won’t be the same inversions, so it may feel balmy right from the trailhead. 

If you go poking around higher, rocky, and complex terrain, there could be a few lingering isolated wind slabs. These spots will be hard to predict and assess. Take a good look at these slopes for signs of wind loading before jumping in. 

Several travelers on Monday reported rollerballs from rocky slopes. A few noted wet loose avalanches that likely released on Sunday. Higher in the terrain wind affected snow was the norm.  At the moment, the snowpack consists of three general markers. 1. The 12/24 thin breakable crust sits about 12-18 inches below the surface. 2. The thicker 12/18 crust is mid-pack. And 3. The basal atmospheric river snow rests at the base of the snowpack. Observations show a generally strong and well settled snowpack. 

Even with all the new snow, travel is tricky, especially at lower elevations. Open creeks, random holes, and grabby bushes can make many normal routes take longer than expected.

Régions couvertes