Bulletin d’avalanche

East Slopes South

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 5 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Avalanches in wind-drifted snow at upper elevations are the main concern. Steer around wind-loaded slopes greater than 35 degrees, especially in areas closer to the Cascade Crest. Shallow snow cover will continue to create challenging travel and increase the consequences of even a small avalanche.

Problèmes avalancheux

  • Wind Slabs

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

    Light snowfall and shifting winds will continue Wednesday, creating fresh drifts and thickening existing slabs.  Avalanches will become larger and more sensitive to triggers as you climb up in elevation, especially in areas with a deeper snowpack further west in the zone. Pay attention as you transition into wind-affected terrain and use caution around ridgelines, rollovers, and rocky outcrops. Evaluate snow and terrain carefully and look and feel for signs of wind-loading like cornices and changes in snow surface texture and hardness. In wind-sheltered areas, you may find unconsolidated snow with loose dry sluffs possible on steep, unsupported slopes.

Avalanche Discussion

Since 12/8, 2-4ft of new snow fell throughout the East South Zone. We have minimal observations and a lot of uncertainty about snowpack conditions near and above treeline. In areas near the Cascade Crest, a layered winter snowpack is developing. Far to the east and at low elevations, snow cover is shallow, and below the threshold to produce avalanches. On shady aspects at upper elevations, the snowpack may be building on weak, sugary, old snow. The variability may be the biggest challenge. Gather information as you travel and pay attention to changes with aspect and elevation. If you observe recent avalanches, shooting cracks, or collapses, move to simple, low-angled terrain.

Preliminary Report: On Saturday morning, December 11, a party of six backcountry tourers were traveling uphill in a closed section of the Crystal Mountain Ski Area known as Silver Basin. The party triggered a large avalanche on an NE to E facing slope at approximately 6600ft. While all members of the party were initially caught, four were fully buried. A nearby party of two witnessed the event and immediately assisted in the rescue. Crystal Mountain Ski Patrol was also notified and responded to the scene. Unfortunately, one of the fully buried victims did not survive. NWAC and Crystal Mountain Ski Patrol will collaborate to conduct an investigation. Our deepest condolences to the family, friends, and community. 

SS-ASu-R3-D2.5-U; Crown Depth: estimated 2ft deep.

We are excited about issuing daily forecasts for the East South zone this season, but we need your help in making this successful. If you get out in the mountains this winter, please send us your observations.  - The team at NWAC 

Régions couvertes