Bollettino valanghe

East Slopes South

Northwest Avalanche Center
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Pericolo valanghe

Sun
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Variable and potentially weak old snow surfaces exist, and you could trigger avalanches in new and wind drifted snow. Use small test slopes to see if new snow slides easily and feel for stiff over soft layering. If you find snow sliding easily or see shooting cracks from your feet or equipment, you should steer around steep slopes or move to wind-sheltered terrain.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Another storm may bring 8-10" of new snow to East South, and Wednesday's storm buried various older weak surfaces and slick crusts. Observations from the nearby White Pass area showed preserved, buried surface hoar in some locations. In the adjacent East Central zone, reports showed avalanches running on melt-freeze crusts on southern aspects. These weak interfaces will take some time to heal and, when buried deeply by wind drifted snow, could produce large avalanches that propagate widely. Shifting wind directions and new snow may make it challenging to identify wind-loaded terrain. Use your probe or pole to feel for stiff snow layers over softer layers. Quick hand pits can show you how easily this stiffer snow will slide. Steer around steep slopes where you find evidence of wind slabs or stick to wind sheltered terrain. 

    The old crown of a recent slab avalanche in wind drifted snow in the Ahtanum Meadows area. The 1F hard slab failed on softer 4F snow below.

    East aspect, 6800 ft

     

    Photo: Katie Warren

Avalanche Discussion

Last week, I traveled into the Ahtanum Meadows area and found approximately 7 inches of new snow over the Christmas Crust at lower elevations and nearly 2 ft at higher elevations. Since the recent snowfall, this crust is likely buried over 3-4ft deep near and above treeline. Overall, I found a favorable bond with this stout crust. However, in some locations in the eastern Cascades, this interface is beginning to weaken and will be something to monitor going forward. 

A complex snowpack exists in many areas of the eastern Cascades with weak faceted snow and surface hoar potentially buried on sheltered northern aspects, and steep southerly aspects may have a slick melt freeze crust underlying the most recent storm snow. It will be essential to monitor how the new snow reacts as you travel. Slight variations in aspect could have very different avalanche conditions. Use quick hand pits and small test slopes to observe how well the new snow bonds to underlying surfaces. If you find reg flags such as shooting cracks, collapsing, recent avalanches, or new snow that slides easily, dial back your terrain choices to low angle slope. 

If you get out into the East-South, let us know what you see by submitting a public observation. 

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