Avalanche forecast

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Northwest Avalanche Center
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Avalanche danger

Sun
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Large and dangerous slabs are primed for human trigger following a very significant snow and wind loading event. Wind slabs at any elevation may be firm, propagate widely, and entrain plentiful recent snow. Travel safely on slopes less than 35 degrees, giving a safety margin to large, steep terrain features.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2–3

    We have a lot of uncertainty at upper elevations, but it's safe to say that sustained SW winds transported large volumes of snow during the recent storm cycle. These slabs formed within denser snow sitting atop lower density snow that accumulated prior to Wednesday. Slabs may be firm, widely propagating, and easily triggered on or under steep slopes. Give these thick slab layers time to heal and any potentially wind-loaded slopes a wide margin of safety. Look for signs of wind affect including recent drifts, wind lips, and firm or punchy snow layers. These could be present at any elevation given plentiful evidence of large wind drifts even in the Methow Valley. Avalanches could run on or step down to older layers in the top 3 feet of the snowpack, especially on steep SW-S-SE aspects. Such avalanches could be very large with low chances of survival. 

    (1/7/2022)

    Example: This very large avalanche was triggered by explosives on 1/7. The very deep (4-6') and wide (500ft) failed on an old snow layer, grew very large (D4) and broke trees. HS-AE-R4-D4-O, NE, 6800. 

    Photo: Crystal Mt Ski Patrol

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2.5

    An estimated 3-4 ft of snow accumulated since January 5th at Washington Pass, adding 25% of the current snow depth during that time.  Mazama also picked up nearly 2 ft of snow during the same time period. Snowfall finally tapered off early on Friday afternoon. It's safe to say that there's plenty of recent snow to form a large slab in any wind-sheltered terrain. You'll need to approach the terrain with an assessment mindset.  Use small test slopes to identify weaknesses within the storm snow and on the 1/5 new/old snow interface. At lower elevations west of the Silverstar drainage, you may find a crust within the recent storm snow layers as reported here. Avoid all slopes steeper than 35 degrees, particularly if you see shooting cracks, hear whumphs, or identify layers that fail easily and cohesively.

    Touchy slabs may be present throughout the sagebrush hills in the Methow Valley particularly where they likely overly basal facets, a layer of weak snow just above the ground that likely weakened during the late December / early January cold snap.  Impacts of avalanches could include low elevation terrain where they are rarely a concern and roof avalanche hazards.  Use caution near any steep, snow-covered slopes around town and near large roofs holding snow. Several near-death roof avalanches occurred late Thursday and Friday. This potential remains until cold temperatures return to low elevations.

    (1/7/2022)

    Large slab avalanches in open hillside terrain of the Entiat drainage. North aspects around 1,500ft

    Photo: Ryan Graig

Avalanche Discussion

The snowpack has seen a rapid change in depth, snow density, temperature, with significant wind loading. We're just coming out of lengthy natural avalanche cycle. Information remains limited in much of the zone. Approach the terrain cautiously and give our heavy, dense new snow layers some time to settle.

 

Regions covered