Lawinenlagebericht

West Slopes Central

Northwest Avalanche Center
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Lawinengefahr

Tue
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist 3 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

You can trigger an avalanche in wind drifted snow at and above treeline. Identify and avoid areas where the wind created deeper, denser drifts to reduce the likelihood of triggering an avalanche. Morning sun could initiate wet avalanche activity.

Lawinenprobleme

  • Wind Slabs

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

    As the latest batch of wind slabs stabilize, the places where you could trigger one become more scattered. Common trigger points are directly under top and cross-loaded ridges, on convex rollovers and gully walls, or around cliffs and rock outcroppings. Slab avalanches should generally be small, but cornice fall could trigger a larger slab where a single person might not.

    Anticipate more and larger wind slabs in other parts of West North, especially near the Cascade Crest (Ruby Mt, Hidden Lakes, etc). These areas saw stronger east winds Saturday.

    Look for recently scoured ridgelines and other wind affected features to identify the pattern of wind loading in the terrain around you. Test slopes and hand pits can help you monitor differences in layering as you change aspects and gain elevation. Evaluate the bond of wind slabs and ease into steeper terrain - or just find a lower-angled line around features where you are more likely to trigger one.

    Example of small wind slab avalanche in wind affected, alpine terrain.

Avalanche Discussion

Avalanche activity on the West Slopes was a combination of small wind slab and wet loose avalanches. Some areas saw a decent amount of sun and warming temperatures that triggered a round of wet avalanches. Stevens Pass saw less sun today but a rider triggered wind slab avalanche (D1.5) was reported from a SE aspect below ridgeline. Human triggered wind slabs (all D1) were reported from Snoqualmie Pass.

The sun should make a return Monday morning. Take note of the amount of warming and give some space to steep slopes that show signs of instability like rollerballs. Also worth noting is it was the first day since February 21st with near or above freezing temperatures at 5000'.

Two cornice fall triggered slab avalanches in West North were the most notable events over the weekend (obs, obs). Cornices grew large and unstable in the past month with colder temperatures, plenty of snowfall, and wind. These avalanches are a sign cornices are a hazard to backcountry travel for the rest of the winter and spring.

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