Avalanche forecast

East Slopes North

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

E-SE ridgeline winds will increase later tonight and Wednesday forming fresh wind slabs above and potentially near treeline.  This wind direction can form wind slabs on different aspects than the usual storm pattern.  While most new wind slabs will be shallow, if you experience shooting cracks or see new avalanches, stay off of similar steep slopes. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Over the next 2 days, we'll see E-SE ridgeline winds generally ramp up and move an increasing about of loose snow near and especially above treeline, gradually increasing the likelihood that you'll find and trigger a wind slab avalanche.  Use caution on lee steep slopes below ridges, steering around convex rolls and avoiding steep terrain below the base of cliffs.  You can feel for stiff over soft snow layering and look for signs of cracking to identify areas of potentially unstable, wind-drifted snow.  Cornices that formed during recent periods of strong W-SW winds may not help you identify which slopes are wind-loaded. 

    In wind-sheltered and very steep terrain, small dry loose avalanches are possible with periods of light snowfall continuing.  Use caution near terrain traps like above cliff bands or tight gullies where a fast-running sluff could knock you off your feet in the wrong place. 

    (2/23/2023)

    Cracks break through wind-drifted slabs on a southeast aspect near treeline near Whistler peak.

    Photo: Will Govus

Avalanche Discussion

Avalanche conditions have been relatively quiet since Friday, with dry loose avalanches or the occasional small wind or storm slab reported over the last few days either near or above treeline.  Over the last 48 hours, temperatures have stayed cool and generally below freezing and mostly cloudy skies along with periods of light snow have limited the number of sunbreaks and the sun's influence on southerly slopes.  On Sunday,  NWAC observer Willie Webster went to the upper Twisp River drainage and reported triggering a small slab avalanche that ran 8-12" deep on the 2/25 crust (see below).  He also reported long-running loose avalanches. 

Observers reported 3 large (size D2) natural slab avalanches on northeast aspects of the Hairpin valley near Washington Pass that likely occurred on Friday. 

Near Washington Pass, the Valentine's crust is 2-2.5 feet below the surface. There have been some isolated reports of weak snow adjacent to the crust though it's generally not a current concern for avalanches. The January 5th surface hoar can still be found over 3 feet below the surface on many slopes. You may be able to identify the layer as a grey stripe or with planar results in snowpack tests. The layer isn't currently a concern for avalanches.

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