Boletín de aludes

East Slopes Central

Northwest Avalanche Center
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Peligro de aludes

Tue
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 4 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

There is still a possibility of triggering avalanches in wind drifted snow at upper elevations. Areas near the Cascade crest, such as Salmon La Sac, may receive more snow, and larger avalanched are possible. Identify these wind-loaded pockets near ridgelines by their pillowed look and steer around them if you see signs of instability, such as shooting cracks. 

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–1.5

    There hasn't been much new snow east of the Cascade Crest, but a continued trickle-in of snow with stronger winds in the forecast will likely form shallow wind slabs on lee aspects. These slabs may form over slick crusts on southern aspects or weak faceted snow on more northerly aspects and be easy to trigger. While we anticipate most of these avalanches to be small, areas near the western edge of the zone or close to the Cascade Crest may receive more snow, and wind slabs that form may be larger in these areas. Be cautious of the surrounding terrain and any features such as cliffs, gullies, or rocks that may increase the consequences of being caught by even a small avalanche. Look for clues to how wind-drifted snow may react before entering larger features. For example, you can check to see how easily the snow slides with hand pits, skin track tests, and small test slopes. Also, look for shooting cracks and small slabs as indicators that you could trigger an avalanche. 

    (2/4/2023)

    Small fractures on a test slope in a wind-affected area are great clues to instability.

    Photo: Katie Warren

Avalanche Discussion

Around 1-3 inches of snow fell over the weekend in most areas throughout the zone, with slightly higher amounts near the Cascade Crest. Areas further east, such as Mission Ridge, also picked up a nice refresh of around 4 inches. This new snow may have preserved weak snow layers on northerly aspects at higher elevations and put a dusting of snow over thick crusts at lower elevations. With very mild temperatures on Monday, you can expect to see some rollerballs or small wet loose avalanches that run on these slick crusts at lower elevations. In the last couple of days, I have been to the westernmost and easternmost edges of the East Central zone. Not surprisingly, snowpack conditions in these locations are quite different. A deeper and stronger snowpack exists in the western portion of the zone, and further east, a shallower snowpack with more prominent and concerning buried weak layers. Common landmarks in these snowpacks are the MLK crust and the Christmas Crust, buried .5-1.5ft deep and 3-4ft, respectively. The recent cold weather weakened the snow above and below the MLK crust into weak, faceted grains. As new snow begins to add up, this creates a weak structure that we'll have to watch closely. In the lower Little Wenatchee River Drainage, I found 300cm of snow at 5600ft that increased in strength with depth. Just outside of the Mission Ridge Ski area on Sunday, I found 230cm of snow, and while much of the snowpack was strong 1F or P rounded grains, two prominent layers of buried surface hoar exist. The lower layer of surface hoar, buried on January 4th, is still producing propagating test results, despite being below the MLK crust. The more recently buried layer of surface hoar, buried on January 18th, is just beginning to accumulate enough snow to become a problem with future storm events. 

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