Bulletin d’avalanche

East Slopes South

Northwest Avalanche Center
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Danger d’avalanche

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

Points saillants

The snowpack is still recovering from several inches of new snow and strong winds. You’ll find the most dangerous conditions in wind-loaded terrain, but don’t write off steep, open slopes in more sheltered terrain either. A poor snowpack structure and recent weather inputs should help keep your terrain selection conservative, especially in areas closer to the Cascade crest. 

Problèmes avalancheux

  • Storm Slabs

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

    Storm instabilites may linger on Monday. Depending on where you are in the East South, you may find 3-8 inches of new snow resting over weaker snow from our recent cold snap. Expect these slabs to be most prevalent closer to the Cascade Crest or in wind-loaded terrain as you gain elevation.  This weaker snow is shallow enough that it should be easy to locate using hand pits or small test slopes. Default to less steep, more sheltered terrain if you notice shooting cracks, whumphs, or active wind transport.  

    (12/31/2024)

    An example of a small storm slab. 

    Photo: Joe Dellaporta

  • Persistent Slabs

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

    Triggering a large, 1-2 foot thick avalanche on a buried weak layer remains a concerning possibility in the East South zone. Several inches of new snow and a good dose of strong winds may help wake up this weak layer, especially closer to the cascade crest that received more new snowfall. An NWAC Forecaster traveling on the nearby Mt Adams reported a whumph on a wind loaded feature on Saturday. Under further investigation, they found this weak, faceted snow 2 feet below the surface as the culprit. 

    While we all hope we can receive a warning sign before these avalanches occur, that is not always the case. These persistent slabs can break without warning and could wrap around terrain features easily making for an unsurvivable avalanche. 

    Due to this, the best mitigation strategy is to simply use lower, angled terrain out of the wind. Steep wind loaded slopes are most suspect, but any open slope greater than 30 degrees is guilty until proven otherwise. 

    (2/15/2025)

    A profile near a whumph that I recieved along the South Climb road on Mt Adams. This occured on a small east aspect, wind loaded feature. While I got a propagating test result in this spot, I didn't a few feet over in a less wind loaded spot. 

    Photo: Joe Dellaporta

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