Bulletin d’avalanche

East Slopes North

Northwest Avalanche Center
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Danger d’avalanche

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

Points saillants

Very warm temperatures and filtered sun will increase the chances of avalanches as the day progresses. While the most obvious avalanches will be small wet loose slides, be on the lookout for larger falling cornices. Give yourself options to move off steep slopes before they become wet and weak, and don't linger below cornices and rock slabs that could shed snow. 

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely
    Taille
    2–3

    This problem may still exist in areas with shallower snowpacks east of Mazama. Falling cornices could trigger these avalanches. Meltwater from warming could also initiate slides.  If you’re in an area with less 6 feet of snow on the ground, or venturing to far-flung parts of the zone, keep this problem on your mind. If you dig and find a layer of weak sugary facets in  the middle of the snowpack, steer away from steep, open slopes.

    (3/17/2025)

    A widely propagating avalanche near Tiffany Mtn.

    Photo: Willie Webster

  • Loose Wet

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

    If you see recent avalanches, rollerballs, or wet, weak snow that slides easily, move to more frozen or lower-angle slopes. Be ready for dynamic and changing conditions during this significant warm-up. The avalanche danger will increase throughout the day and will be more elevated on specific slopes. Use extra caution around steep, rocky terrain where avalanches could be more likely and bigger.

    Loose avalanches triggered by snow falling off rocks. Photo: Adam Butterfield

  • Cornices

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

    Many ridgelines are thick with cornices, and the current warm-up is the prime condition for them to fall. Try to avoid traveling on slopes below large cornices. You can minimize your exposure by avoiding areas under them and only stopping in places that are not threatened by these overhead hazards. While on ridges, stay far back from the edge, and don't travel on overhung snow. Gaping cracks in the snow can indicate that a cornice is ready to fall.

    (4/2/2025)

    Cornices loom at 7,400-7,500ft above northeasterly aspects in the Hairpin Valley.

    Photo: Josh Hirshberg

Avalanche Discussion

The current warm-up is changing the snowpack. Slopes that didn't already slide in late March could be tested further.

In the higher portions of the terrain, pockets of dry or wind-blown snow may still linger. This snow may become unstable as it gets warmed for the first time. Below 4,000ft some slopes are bare or lacking enough snow for avalanche danger. This is especially true on sun-exposed slopes or those that are far to the east of the Cascade crest.

Régions couvertes