Bollettino valanghe

East Slopes North

Northwest Avalanche Center
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Pericolo valanghe

Thu
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 3 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

You could trigger large old wind slabs in big, steep starting zones above 5,500ft, and smaller ones due to increasing winds later in the day. Warming snow surfaces in the sun may cause small wet loose slides to run on steep slopes. Look and feel for signs of wind textured or wind stiffened snow, and identify areas you'll want to avoid.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Wind slabs could take on various forms on Wednesday. They could be small and soft, or they could be large enough to bury or kill you. Later in the day, winds may drift snow at ridgelines and create shallow soft slabs. In some isolated areas, you could trigger a larger and more surprising slab on a crust from mid February. Look for drifts near exposed terrain as you gain elevation, below large rock outrops, and near cornices. Hedge your bets by steering clear of large unsupported starting zones with unfavorable consequences.  Identify obviously wind-loaded or wind textured terrain of concern. 

    You can use small test slopes and quick, informal tests to see how the snow reacts. Look for strong over weak structure, and travel accordingly.

    (2/28/2023)

    Shooting crack on a wind drifted slope.

    Photo: Matt Primomo

  • Loose Wet

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

    Small loose wet slides may become commonplace on steep slopes that catch direct sun. Look for signs of moistening snow, snow falling from trees and cliffs, rollerballs, and fresh fan shaped slides.  These could run a respectable distance because they'll slide on a recent crust. The debris could entrain a fair amount of snow and create debris piles that you won't want to get caught in. Especially be careful of larger terrain like rock lined couloirs, gullies and similar places where debris piles up deeply.

    (2/14/2023) Example small, solar induced loose slides.

    Photo: Andy Harrington

Avalanche Discussion

Observers reported ski triggering a small windslab in wind stiffened snow that was about 10" deep at the top of a slope near Washington Pass on Tuesday. Another small ski triggered slide was soft, and about the same depth. You'll find about 12-18" of new, low density snow since Sunday. Winds have been switching direction, so you could find wind slabs on all aspects. 

Cornices are becoming larger, and worth being mindful of. Last Friday, a group triggered a large cornice fall after they felt a collapse while standing on a ridge near Tower Mountain.

You'll often find a crust from mid February 1 to 2.5ft down, depending on elevation, aspect, and proximity to the crest. This crust can be found up to at least 7,000ft, and is shallower at lower elevations and further east in the range. We've seen minimal avalanche activity on this layer, but it'll be worth monitoring as snow adds up on it.

Regioni coperte