Avalanche forecast

West Slopes Central

Northwest Avalanche Center
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Avalanche danger

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

It is likely that you could trigger a large avalanche on steep, unsupported slopes in upper elevation areas on Wednesday. Avalanches could occur as deep as the old snow surface, and could be large enough to bury, injure, or kill you, so consider avoiding those upper elevation areas. If we see any sun, wet loose avalanche could occur, or they might occur on all aspects if low cloud cover persists. 

Avalanche problems

  • Storm Slabs

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

    A few large slab avalanches occurred with triggers in the West North Zone on Tuesday, with conditions similar to what you might see in the northern half of the West Central Zone. There were also a few storm interfaces noted around 6 inches and a foot down, but they are expected to heal quicker than the deeper avalanches. The deeper avalanches occurred just above a crust, probably involving a weak layer. This problem is not easy to identify and avoid. We currently know little about it after the large storm which just deposited 3 feet or more of snow at upper elevations.

    You're most likely to trigger one of these large, deadly avalanches in the upper portions of near treeline and above treeline areas.  Expect them to occur on large, steep, unsupported slopes. Until we know more about this weak layer, consider avoiding these unsupported slopes at angles greater than 35 degrees.  An unsupported slope refers to a slope that rolls over into steeper terrain, without an abrupt transition to lower angle terrain under the steep rollover within a short distance. Pay attention to the usual signs of unstable snow such as cracking and whumphing, but these indicators are probably not precursors that you will find before triggering one of these deeper avalanches. 

    (3/15/2022)

    An large slab avalanche which was triggered in the West North Zone on Tuesday.

    Photo: Adam Ü

  • Loose Wet

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

    Wet loose avalanches occurred in the new snow at lower elevations on Tuesday.  These avalanches will remain limited to the new snow layers. Snow finally fell in below treeline areas Monday night onwards. There is around a foot of snow at the upper portions of below treeline elevations, and the little snow which is there could easily slide on the old, hard snow surface. More snow as we gain elevation could mean wet loose avalanches might run deeper, up to large in size, but probably only entraining the upper portion of the new snow layer which gets moist, up to the top foot or so. If skies clear expect to see avalanches mainly on south-facing slopes. If low clouds persist, they could trap moisture and heat, resulting in wet loose avalanches occurring on more aspects than just the southerly half of the compass.

    If you notice snow surfaces getting moist, pay attention to rollerballs or small avalanches coming down, or whether you find it easy to trigger one yourself. If this is the case, steer clear of steep slopes in locations where you find the moist snow conditions, shifting to other aspects or sticking to lower angle terrain.

    (3/14/2022) Small loose wet slide in motion Monday in the Stevens Pass zone. Photo: Matt Primomo

Avalanche Discussion

Limited information is known about conditions in the West Central Zone at this time, but plenty of observations from neighboring zones exist. If you're planning on heading out, check neighboring zones, as conditions vary greatly from one side of this zone to the other and similarities likely exist with the neighbors. If you travel to areas with a thinner new snow layer over the old snow, you might encounter pockets of reactive wind slabs. Stick to smaller slopes and pay attention to signs like cracking before heading out onto larger slopes. It's important that you evaluate conditions carefully and make decisions before making your way out into avalanche terrain. 

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