Lawinenlagebericht

West Slopes Central

Northwest Avalanche Center
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Lawinengefahr

Mon
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Kernpunkte

Deep and destructive avalanches remain possible, especially in the south and east portions of the zone. Approach terrain with a conservative mindset, and avoid traveling on or below large open slopes steeper than 35 degrees, or in their runouts down on the valley bottoms. Avoid steep slopes with recently formed wind slabs, as the snowpack is adjusting  to the new snowfall. 

Lawinenprobleme

  • Deep Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Unlikely
    Größe
    3

    Neighboring zones to the south and east reported very large avalanches failing 10 or more feet deep on the mid-January persistent weak layer. The most recent ones were on March 1. Last week's avalanche cycle was evident in the West Central zone with several aerial photos of deep persistent slab avalanches. The weight of just a person may not be enough to cause an avalanche on this layer, but cornice fall or smaller wind slab avalanches could add the needed weight to trigger an avalanche on this layer. 

    Continue to dial back your terrain selection and build in a wide margin for error. Even traveling along the valley floor well below treeline may seem safe but it is risky. If there are sparsely treed or open slopes above you which eventually lead to large steep avalanche paths, an avalanche failing up there could probably hit you. Take a look at the Highway 20 avalanche and the Monte Cristo trail as examples, in the media gallery below. Seek out simple, lower angled slopes and avoid going into, or underneath open or sparsely treed terrain with those large steep start zones above you.

    (3/1/2021) This very large avalanche occurred on the east facing slopes near Peak 7185 south of Mt Misch. The crown line was estimated to be 10-15ft at its highest point, and 700-800ft wide. Photo: John Scurlock

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1

    Wind slab avalanches are possible on steep, wind affected terrain at mid to upper elevations. In the West North zone a human triggered avalanche occurred Saturday afternoon, burying them up their knees.  This was on a slope that had already been skied several times that day. Another larger natural avalanche was spotted nearby, possibly triggered by a cornice fall. They received more wind and snow than us in the West North zone, but conditions are not too different. 

    Avalanches in the new snow,  a foot or more deep, could be large enough to bury, injure, or kill you. Strong winds redistributed snow onto leeward slopes and crossloaded features. Feel for stiffer snow and search for pillowlike or textured deposits to determine where wind slabs are.  Avoid wind loaded slopes steeper than 35 degrees.

    (3/6/2021) A small human triggered avalanche in the Blueberry Chutes (north facing, 4500ft) in the West North zone, which occurred Saturday afternoon. The person was buried to their knees, and we're glad to hear that they were uninjured.

Avalanche Discussion

Over a foot of snow fell since Thursday evening in the West Central zone. Even more snow fell at higher elevations, unlike lower elevations that started as rain. Exercise caution as we’re continuing to receive more snow, and avalanches are becoming more common with increasing snow. 

Several adjacent zones are in a prolonged period of unstable conditions with ongoing natural and human-triggered avalanches failing on the deep persistent layer. We suspect that conditions in the West Central zone are similar, especially in the southern and eastern portions of the zone. The deep slab problem continues to pose high consequences and demands a conservative approach to terrain and travel choices. 

Reporst of recent deep slab avalanchesof includes avalanches which closed Highway 20 near Newhalem for nearly a week, and very large natural avalanches from last week on Benchmark and Fortune Mountains just north of Stevens Pass in the West Central zone. The avalanche near Mt Misch north of Green Mountain (photo in Avalanche Problem 1) is alarmingly large.  On Monday, WSDOT avalanche teams triggered an 8ft deep D3 avalanche on the southeast face of Rock Mountain east of Stevens Pass, along with several D2 soft slab and wet loose avalanches. On Sunday, a natural D3.5 occurred in upper elevation north-facing terrain in the Chiwaukum Range on the eastern edge of the Stevens Pass zone, and a natural D3.5 failed on Chair Peak (Source Lake) in the Snoqualmie Pass zone. See photos below for several of these large avalanches.

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

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