Bulletin d’avalanche

East Slopes South

Northwest Avalanche Center
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Danger d’avalanche

Sat
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré 5 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Recent snow and wind formed fresh drifts at upper elevations where you can trigger a large avalanche on slopes 35 degrees and steeper. Look for cornices and textured surfaces to help you identify wind-loaded slopes you want to avoid. Evaluate the new snow carefully, and default to lower angle terrain if you observe recent avalanches, shooting cracks, or collapsing.

Problèmes avalancheux

  • Wind Slabs

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

    You could find different generations of winds slabs made up of snow both new and old. Avalanches could break a few thick at upper elevations and even grow large. You are most likely to find areas of unstable, wind-drifted snow on the leeward side of exposed features including ridges, gullies, and rocky terrain. Pay attention as you transition into wind-affected terrain and look and feel for changes in snow surface texture and hardness. With snow depths tapering from west to east, expect larger and more sensitive wind slabs in areas closer to the Cascade Crest. 

    (12/28/2021)

    Look for fresh cornices along ridgelines as an obvious sign of wind loading.

    Photo: Andy Harrington

  • Loose Dry

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

    Recent storm snow is cold, dry, and cohesionless in many wind-sheltered areas and at lower elevations. Loose-dry sluffs could run far and fast on unsupported slopes steeper than 35 degrees. These avalanches could knock you over, push you into rocks, or bury you in confined terrain. Ease into terrain slowly and consider the consequences of even a small avalanche when choosing slopes to ride or avoid.

    (12/26/2021)

    Example photo of small dry loose avalanches below treeline at Hurricane Ridge. SE, L-N-R1-D1-S.

    Photo: ONP Rangers

Avalanche Discussion

Bumping Ridge and Lost Horse SNOTELS reported around 8in (.5in WE) of new snow over the past 24 hours. New snow fell with warming temperatures and winds blew out of the west with gusts in the 20 mph range. Conditions look to dry out Friday with cooling temperatures. There may even be some clearing skies and sunshine in the afternoon. 

There are still exposed rocks and trees in areas further east in the zone and at lower elevations. The deepest snowpacks are around Mt Aix and Bumping Ridge. The solstice crust is buried approximately 2-3 feet deep near the Cascade Crest and less than 1ft deep in the eastern parts of the zone. Current reports indicate that the storm snow is bonded well to the solstice crust. However, we have limited observations from the upper elevations, resulting in significant uncertainty about snowpack conditions in alpine areas. There have been reports of weak snow surrounding the December 8th melt-freeze crust in neighboring zones. It is worth approaching new terrain slowly and evaluating the snowpack as you venture into higher elevations.

If you are out riding in the East South Zone, please let us know what you see by submitting an observation. 

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