Avalanche forecast

East Slopes South

Northwest Avalanche Center
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Avalanche danger

Mon
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Expect stormy weather and dangerous avalanche conditions in and around alpine areas. You can trigger avalanches big enough to injure or kill you in areas where the wind deposits snow into deep drifts, especially in areas close to the Cascade Crest. Choose conservative terrain and be cautious of early season hazards.

Preliminary Report: On Saturday morning, December 11th, an avalanche fatality occurred in Silver Basin area of Crystal Mountain Ski Resort. See the forecast discussion below for additional details.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2

    Significant winds will continue to transport snow to the lee sides of ridges and rollovers. These strong winds sometimes build slabs lower down on slopes than you may expect. You are most likely to trigger wind slabs near alpine areas, but small wind slabs are also possible at lower elevations. Travel slowly and pay attention to how the snow feels underneath you. Identify areas where the snow feels stiff or hollow and avoid these steep slopes and starting zones.  Today is a good day to stick to low-angle, or wind-sheltered slopes.

    (12/9/2021)

    Example:  Shooting crack in wind drifted snow in Sand Canyon on Mt Hood (E aspect, 6200ft).

    Photo: Andrew Kiefer

Avalanche Discussion

Avalanche season is here. We’ve received several reports of human-triggered avalanches throughout the cascades, including an accident and related fatality near Crystal Mountain. (See preliminary report below) Overnight snow totals ranged from 2 inches in the eastern parts of the zone to 20 inches closer to the Cascade Crest. With this east-west trend, expect elevated avalanche danger closer to the crest and lower danger moving east. 

With continued snow and moderate winds, conditions are changing rapidly, and it will take time for the new snow to stabilize. We have minimal observations and a lot of uncertainty about snowpack conditions near and above treeline. In areas near the crest, it is possible avalanche danger may reflect zones west of the crest. In areas further east, the snowpack is still below the threshold to produce avalanches. Use your probe to investigate snowpack depths as you move through the terrain and hand pits or small test slopes to help identify how well the new snow is bonding to the underlying surface. However, remember that there is a lot of variability, and the snow on one slope may react differently than a similar slope around the corner. 

At lower elevations, you are unlikely to trigger avalanches in areas with vegetation, tree cover, and talus. There isn’t quite enough snow. However, isolated areas with smooth grassy slopes may produce small avalanches. With the early season snowpack, even small avalanches can have high consequences if you impact rocks, trees, or creeks. 

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 a N to E facing slope at approximately 6500’. While all members of the party were initially caught, four were partially or 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.

Uphill travel reminder: Check in with your local ski area this weekend regarding terrain

While we're excited about issuing daily forecasts for the East South zone this season, we need your help in making this successful. However and whenever you recreate in the mountains this winter, send us your observations.  - The team at NWAC 

Uphill travel reminder: Check in with your local ski area this weekend regarding terrain access and parking updates. Closed ski areas often share a similar snowpack and avalanche hazard as the surrounding backcountry. You may also encounter other hazards like active avalanche mitigation, unmarked obstacles, snowmobiles, groomers, and other heavy equipment as ski areas prepare to open. Be prepared to make your own assessments and handle emergencies.

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