Bulletin d’avalanche

East Slopes North

Northwest Avalanche Center
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Danger d’avalanche

Fri
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 4 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

On Thursday, east wind will transport new snow and form fresh slabs at upper elevations.  Use caution on steep, wind-loaded slopes where it will be easy to trigger avalanches near ridges and below cornices. Consider the threat of cornices falling from overhead slopes and a chance for avalanches in less wind-affected terrain. 

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–2

    It will be easiest to trigger avalanches above treeline. Avoid leeward and wind-loaded slopes immediately below ridgelines and cliffs.  If you're on a  ridge, give cornices a large berth as they can break further back than expected. Stay well out from under cornices that loom overhead and refrain from stopping where a falling cornice could hit you. Expect active wind loading and plumes of blowing snow to indicate which slopes will be forming fresh slabs. Winds should be out of the east and may be stronger than on previous days.

    You may see dry loose avalanches on very steep slopes and in wind-sheltered terrain.  If you see fast-running point releases, use caution near terrain traps like rocks, gullies, and cliffs.  

    (2/17/2023) An example of wind-transported snow forming slabs on the left side of a ridge. Photo: Drew Lovell

Avalanche Discussion

Avalanche Fatality: Colchuck Pk, East Central Zone: Read the preliminary report here.

Forecast Discussion:

Expect another cold and blustery day. Plan to bring plenty of extra layers and stay vigilant to prevent cold injuries like frostbite.

Over the last few days, observers have reported about 10-18" of snow over the 2/12 crust near Washington Pass (the crust is present up to about ~7000') with less new snow for areas further east. On Wednesday, avalanche professionals in the Washington Pass area reported variable heights of recent snow due to wind effects with up to 18" over the recent crust and some wind-exposed terrain scoured of the recent snow.  In wind-sheltered areas even near treeline in the Cutthroat creek area, the recent snow was well-bonded.

Observers near Harts Pass reported a large (size D2) avalanche that likely occurred on Tuesday due to a natural cornice fall on N, 7,100ft. On Monday, a large natural slab avalanche released below Blue Lake.  Blowing snow was observed near and above treeline and fresh cornices were growing along ridgelines.  This was a continuation of a trend that started Sunday, where shallow wind slabs (4-10") were developing and becoming increasingly sensitive as the day wore on.    Prior to the current storm cycle, The last significant avalanche cycle occurred on Feb 7th. 

Régions couvertes