Bulletin d’avalanche

West Slopes Central

Northwest Avalanche Center
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Danger d’avalanche

Thu
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

Watch for strengthening winds and the first flakes as another storm nears the Cascades. Steer clear of steep slopes holding freshly wind drifted snow. Switch to simpler, sheltered terrain as conditions worsen in the afternoon.

Problèmes avalancheux

  • Wind Slabs

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

    Strong, steady winds with even stronger gusts will surely move some snow around. The amount of instability you find will vary based on how hard the wind blows and how much soft snow is available for transport. Any new snow should be limited to a few inches at the end of the day, but pay attention if snowfall arrives sooner.

    Blowing and drifting snow will show you which slopes are loading up. Monitor the reactivity of fresh slabs throughout the day. Fall back to lower-angle, sheltered terrain when you find significant slab formation or when simple tests like slope cuts and stomping on wind drifted features yield easy results. Shooting cracks or avalanches are also key indicators of instability.

    (2/26/2023)

    Use small, wind-loaded features to test wind slabs.

    Photo: Jason Speer 

Avalanche Discussion

West Central saw new snow overnight Monday, with roughly 6"  in the southern part of the forecast zone based on weather station data. Areas that saw the most new snow probably picked it up from convergence zone-related snowfall that centered between Stevens and Snoqualmie Pass.  The latter picked up 6-8" of new snow and also saw moderate winds that enhanced slab formation on leeward slopes. That zone was also the site of a human-triggered avalanche where a person was caught and carried a short distance. Stevens saw similar activity with shallow but reactive wind slabs on leeward slopes. Most were D1 in size.

Reported activity from West North consisted of a few small pockets of fresh slab and dry loose avalanches running well in soft, dry snow.  A team submitted an observation from March 16-17th from Snowking Mt. on the West Central-North boundary near Cascade Pass. They were able to easily trigger small slabs in plentiful new snow. You can read their observation here

 

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