Bulletin d’avalanche

Stevens Pass

Northwest Avalanche Center
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Danger d’avalanche

Wed
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré last year. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

The most dangerous conditions will be at upper elevations, where you may encounter falling cornices and slab avalanches formed by new snow and wind. Watch for actively blowing snow to point towards areas of danger, and stick to wind-sheltered terrain to avoid triggering large avalanches. At middle and lower elevation slopes, you may be able to trigger small wet avalanches.

Problèmes avalancheux

  • Wind Slabs

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

    You can trigger avalanches in the new and recently fallen snow, especially on leeward sides of ridges where fresh wind slabs will form. Strong southwesterly winds should be actively transporting snow, so the danger will be easy to see. Cracking in the snow and recent avalanches are also red-flag signs of the danger. Use small test slopes to see how easily the snow slides before committing to larger slopes steeper than 35 degrees. Be ready for changing surface conditions as you move through the terrain and climb in elevation. 

    (3/21/2025)

    An intentionally triggered wind slab avalanche in the Swath.Chiwaukum Mtns, NE, 6,300ft

    Photo: Public

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1.5–2.5

    Cornice falls and glide avalanches will be isolated, but they could be very dangerous. They're often big enough to kill a person on their own, and they frequently trigger larger slides on the slopes below.  Minimize your exposure under large, overhung cornices, cliffs holding cornice-like chunks of snow, or other unstable snow features. Ideally, pick a route that avoids crossing under these features. If you must, travel under them quickly and only stop in locations free of overhead hazards. If you're heading into upper-elevation alpine terrain, use extra caution around craggy features and corniced ridges.

    Smaller wet loose avalanches will be likely at low and middle elevations. If you see recent avalanches, rollerballs, or wet, weak snow that slides easily, move to more frozen or lower-angle slopes. Rain and wet snow falling on an already weak, wet snowpack will increase the avalanche danger.

    (4/6/2025)

    A large, cornice-like chunk of snow fell in closed terrain on the evening of April 5th. Cowboy Mtn, NE, 5,700ft

    Photo: Stevens Pass Patrol

Avalanche Discussion

Stevens Pass Patrol reported natural avalanche activity over the last three days. Two large cornices fell on Saturday night and Sunday night, and a couple of small, wet, loose avalanches ran naturally on Cowboy Mountain on Sunday. On Friday, an NWAC forecaster traveled on sun-exposed slopes in the Skyline Lake area. Steep, southeast slopes below 5,000ft softened by mid-morning and were weak enough to trigger rollerballs by 12p. Some isolated areas near rocks were beginning to get unsupportive for boots. 

There's plenty of older avalanche debris from the late-March (23rd-24th) atmospheric river rain event and subsequent warm-up.  As much as 8" of snow accumulated over the rain crust that eventually froze over the past week. On shaded and upper elevation slopes, you may still find this recent snow. It could be reactive as it warms for the first time.

Régions couvertes