Bollettino valanghe

East Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

Wed
Alta quota
1 · Debole
Limite del bosco
1 · Debole
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

Avalanche danger has eased, but keep an eye out for firm wind slabs or active transport at upper elevations. Steer around consequential or unsupported steep slopes if they appear drifted, textured or if you find signs of instability.

Problemi valanghivi

  • Wind Slabs

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

    The danger is low, but there are still some chances to trigger a small wind slab. In the alpine, slopes are more exposed to wind drifting and are more likely to be affected by even light winds. Small wind slabs could form during the day with a switch to westerly winds at ridgetop.

    Pay attention to how the snow changes as you travel. Look for textured surfaces, active transport, or cornice formations. Very steep, convex, and/or unsupported slopes near rock features may be most likely place to actually trigger a slab. Steer around areas that you think could hold this problem if venturing into consequential terrain. Stay back from cornices as they may have grown enough to break off.

    (1/2/2023)

    Small, ski triggered hard slab avalanche near Crystal Mountain. 

    Photo: Barrett Gray

Avalanche Discussion

The few days of clear skies and cool to cold temperatures are beginning to weaken snow surfaces, and surface hoar has grown large in many areas. On Wedge Mountain on Monday these feathery crystals had grown large (>2cm in many areas!) on east and northeast aspects from 4,000ft up to 6,500ft. We found SE-SW aspects had a sun crust, and consistently had a layer of surface hoar on top. The mid layer clouds were higher today than yesterday, so surface hoar grew, but didn't burn off. At lower elevations in the Salmon la Sac, observers have been reporting firm travel on the ice crust. Ridgelines have been experiencing drifting from both east and westerly winds, and Andy found a double cornced ridge near Sasse Mtn on Sunday. On Saturday, avalanche workers at Mission Ridge triggered cornices and small wind slabs with explosives. 

On average, you could expect about 8-18 inches of new snow resting on the Christmas Crust at mid and upper elevations, and north of Blewett Pass even at low elevations. In the further eastern parts of the zone there may be less. Expect to hit this 'bottom' in many areas, and travel could be very slick and slippery, especially on steep slopes. The crust takes the form of an impenetrable ice lens from many hours of freezing rain up to about 4,500ft in the zone. At higher elevations and near the crest, the crust is more opaque and breakable, and may be covered with more snow. In both cases the snow above this crust is weakening and faceting, so it'll be worth monitoring as more storms eventually make their way into the region.

If you make it out to enjoy the mountains, consider submitting an observation!

Regioni coperte