Avalanche forecast

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Northwest Avalanche Center
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Avalanche danger

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

Use caution on steep slopes at higher elevations where you find recently drift snow, it's here you may still trigger a wind slab avalanche.  Cornices have grown large over the last few weeks, make sure to give them space along ridgelines and be aware of the overhead hazard.  While unlikely,  cornice fall could trigger an avalanche on the slope below.  

Avalanche problems

  • Wind Slabs

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

    You are most likely to encounter wind-affected snow on a variety of aspects above treeline on Tuesday.  Use caution on steep slopes below ridges with signs of drifted snow, 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. 

    Winds were stronger several days ago out of the W-SW through late on Friday March 3rd, which is also when several natural wind slab avalanches were noted in the Washington Pass area.  Since then, generally lighter winds out of the E or S may have cross-loaded some slopes and caused fresh drifting along higher peaks and ridgelines.  

    Small loose avalanches are possible in very steep terrain where loose unconsolidated snow lingers.  While more clouds and snow showers are expected Tuesday, the days are getting longer and the sun can work quickly on new snow during extended sunny periods, leading to dry or wet loose avalanches.  Dry loose avalanches remain possible on shadier slopes.  Think about the consequences of a small avalanche near terrain traps like above cliff bands or tight gullies. 

    (3/3/2023)

    In specific places like wind lips on ridge lines we could trigger small wind slab avalanches. Upper Twisp River drainage

    Photo: Willie Webster

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.  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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