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 7 months ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

You may still be able to trigger an avalanche in wind-drifted snow on slopes below ridgelines and at the bases of cliffs. While avalanches are likely to be small, watch for cracking in textured drifts as a sign to steer around very steep terrain where small avalanches carry higher consequences. 

Problemi valanghivi

  • Wind Slabs

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

    Thursday brought 3-5" of snow to the East North zone, along with moderate winds that formed shallow wind slabs near ridgelines and the base of cliffs. Additional light snow accumulation on Friday may obscure textured surfaces. Instead, feel for stiffer snow over softer snow or look for cracking in pillow-like features to identify wind-loaded slopes. These wind slabs may have formed over slick or weak surfaces, particularly at upper elevations. In most terrain, these avalanches wouldn't pose much of a hazard. But in very steep, confined, or cliffy terrain, a small avalanche could cause a dangerous fall. Use extra caution and consider steering around more aggressive terrain features. 

    (1/5/2023)

    An example of a shallow wind slab you could trigger in steep lee terrain below ridgelines at higher elevations.

    Photo: NWAC Public obs

Avalanche Discussion

This storm system will continue to spread light precipitation across the zone, with heavier accumulations farther west. Temperatures will continue to warm, so expect rain to impact areas at the lower end of the middle elevation band. Since there isn't much fresh, dry snow to rain on, we expect that any wet loose avalanche activity will be limited to very steep terrain. But you'll likely see widespread rollerballs in many areas. 

With incoming snow, this is a great time to track the bond with the old snow surfaces. Before this storm, weak snow and surface hoar were widespread at lower elevations, while upper elevations had a mixture of thick supportable crusts on sunny aspects and breakable crusts on shadier slopes. There is a lot of uncertainty about how well the new snow will bond to these widely variable old surfaces. As you travel, track the bond at this new interface using quick hand pits to see how the new snow reacts. If the new snow slides easily as a single cohesive block, avalanches may be more likely as additional snow accumulates. 

Travel conditions have been challenging to say the least. We hope this storm improves conditions, but you should still expect rough surfaces, breakable crusts, and old, frozen rain runnels. Rain and warm snow may soften surface crusts, but it is still advisable to bring equipment to prevent long, sliding falls. Better to have it and not use it than not have it when you need it most. 

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