Bollettino valanghe

East Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

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

In sintesi

A few inches of new snow and moderate winds overnight could build shallow wind drifted slabs where you could trigger an avalanche. The most likely places to encounter these unstable slabs are upper elevations just below ridgelines. Look for textured surfaces or deeper pillows of snow to identify steep, wind-loaded slopes to navigate around. 

Problemi valanghivi

  • Wind Slabs

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

    This storm has been slow to impact the east slopes, but precipitation is forecasted to increase overnight. We likely won't get more than 3-5 inches of new snow, but southerly winds between 20-30mph could quickly form shallow wind slabs overnight. Consider steering around steep terrain if you see actively drifting snow or long cracks that shoot away from you. You can also use visual clues like textured surfaces, cornices, and stiffer snow to identify potentially wind loaded slopes. Due to difficult and long approaches, we have a lot of uncertainty about upper elevations, so be prepared to make your own assessments if you head into alpine terrain. Slick crusts, surface hoar, and weak snow surfaces are prevalent, so new snow could bond poorly with old snow surfaces. Use quick hand pits or test slopes to see how the snow reacts. Avalanches are more likely if recent snow or stiffer wind drifted snow slides easily on old surfaces. 

    (12/23/2023)

    These textured surfaces are a good indication that wind slabs exist on this slope.

    Photo: Matt Primomo

Avalanche Discussion

Well, the Christmas Day storm was a bit of a bust, and most locations in East Central picked up under 2" of snow. Hopefully, the forecast for Monday night doesn't also underproduce, and we see an additional 3-5 inches of snow by Tuesday morning. The cold air pooled east of the Cascades should maintain the precipitation as snow. While the forecast is favorable, there is potential for rain or freezing rain by the afternoon. 

New snow will fall on a mix of melt freeze crusts, sometimes capped with surface hoar or a thin layer of weak snow on shaded or sheltered slopes. These weak or slick surfaces may become problematic when loaded with new snow. So, observe the old snow interface as you travel to see how well the new snow bonds to the old snow surface. Monitoring the old/new snow interface will be especially important at upper elevations where we have limited information.

New snow will help coverage overall but can also bury obstacles, leaving them lurking just below the surface. With plenty of brush to contend with off the trails, exposed boulder fields, and rocks on many slopes, consider using summer trails or roads to access higher elevations. 

You can contribute to the forecast! Let us know what you found by submitting an observation HERE. 

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