Avalanche forecast

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Northwest Avalanche Center
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Avalanche danger

Mon
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

You can easily trigger loose avalanches in steep terrain. Watch for blowing snow to indicate where you may be able to trigger slab avalanches at upper elevations. Identify likely locations for these stiff slabs by their textured, pillow-like surface. Steer around these drifts where you find them in steep terrain and avoid slopes below corniced ridges and the base of cliffs where you are more likely to trigger an avalanche. 

Avalanche problems

  • Loose Dry

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

    Loose avalanches will be easy to trigger on a variety of steep slopes where the surface snow is loose, uncohesive, and slides easily. You'll want to exercise caution near terrain traps like above cliff bands or tight gullies where a fast-running or forceful sluff could knock you off your feet. Watch for wet or sun-triggered avalanches on sun-exposed east through south through west aspects. Sticky, moist surfaces are a good indicator on these slopes. 

    (3/9/2023)

    Small, dry loose sluffs were both running naturally and easily pushed by skiers over recent days.

    Photo: Drew Lovell

  • Wind Slabs

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

    Shifting wind speed and direction will maintain a concern for triggering wind slab avalanches, particularly at the highest elevations. Slopes below ridges, the base of cliffs, and convex rolls are common trigger points. Pay close attention to signs of current and recent wind direction such as drifting patterns. You can also use your probe or pole to feel for stiffer snow over softer snow layers. Cracks that shoot away from your feet or equipment are a sure sign of unstable wind slabs. If you observe these long cracks, use lower-angle routes or move to sheltered terrain. 

    (2/23/2023)

    An example of cracks breaking through wind-drifted slabs near Whistler peak.

    Photo: Will Govus

Avalanche Discussion

Observers reported a handful of avalanches in the past couple of days with natural loose dry avalanches to size D1.5 on Saturday. On Friday, large (D2) wind slabs ran on north, west, and southwest aspects around the Hairpin Valley. Some of these had crowns up to 4 feet deep, where snow sifted off of cliffs to form deeper slabs. 

On Friday, Drew Lovell reported from a prolonged period near Hart's Pass, where his concerns lay in the recent snow and alternated between loose and wind slab avalanches.  Also on Friday, Wille Webster was in the Silverstar area and found up to 3 feet of recent snow since late February. An observer on Wednesday reported a thin sun crust (likely formed Sunday) below the recent snow on southerly slopes, the crust faded away at higher elevations.  Significant snowfall and intermittent wind events since late February have brought loose avalanches or the occasional small wind or storm slab avalanche. In that time, the snowpack has gained close to 3 feet in many locations.

The Valentine's crust is 3-5 feet below the surface in the western half of the zone, including near Washington Pass, the upper Silverstar drainage, and Hart's Pass. You can expect to find it closer to the surface at lower elevations and further east in the zone. There have been reports of weak snow adjacent to the crust though it's generally not a current concern for avalanches. If you're motivated to dig deep enough, you can probably still find the January 5th surface hoar. It's so deep and rounded, that it hasn't been a concern for avalanches in over a month near Washington Pass. We have less of an understanding of the progression of these layers east of Mazama and the Twisp River drainage.  

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