Bollettino valanghe

East Slopes North

Northwest Avalanche Center
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Pericolo valanghe

Sat
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Expect a calm, sunny, and very cold day.  You can still trigger avalanches where recent winds drifted slabs at upper elevations.  Use caution on steep, wind-loaded slopes near ridges and below cornices. Consider the threat of cornices falling from overhead slopes. 

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    It will be easiest to trigger avalanches above treeline. Use caution on 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 out from under cornices that could loom overhead. North and northeasterly winds formed the most recent slabs on Thursday. Earlier in the week, southwest winds also transported snow.

    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 very cold day with sun. Plan to bring plenty of extra layers and stay vigilant to prevent cold injuries like frostbite. You may see some small loose avalanches on steep sunny slopes. 

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 Thursday, observers triggered a small wind slab avalanche in the Swamp Creek drainage at 7,500ft, northeast aspect. On Wednesday, 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. 

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