Lawinenlagebericht

East Slopes North

Northwest Avalanche Center
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Lawinengefahr

Sun
Hochgebirge
3 · Erheblich
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Kernpunkte

After a recent wind event, you can still trigger avalanches in wind-drifted snow 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. 

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1–2

    Strong easterly wind on Friday and ongoing shifting wind direction will maintain a concern for triggering wind slab avalanches, particularly at higher 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

  • Loose Dry

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–1.5

    Loose avalanches will be possible on very steep slopes in wind-sheltered terrain 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

Avalanche Discussion

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. 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.  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.  

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 some 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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