Boletín de aludes

East Slopes South

Northwest Avalanche Center
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Peligro de aludes

Wed
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 3 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Your primary concerns are likely limited to smaller avalanches in wind-drifted snow or wet avalanches on sunny slopes. We don't expect these avalanches to be large, but travel carefully in very steep terrain where a fall or slide could have serious consequences.

Problemas de aludes

  • Wind Slabs

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

    Visual clues such as textured surfaces, corniced ridges, and drift formations around rocks or trees can all point you to wind loaded terrain. Slopes below corniced ridges and confined alpine features like steep couloirs and sharp ridgelines are likely spots for wind slabs. Consider the consequences of even a small avalanche in very steep rocky terrain. Use small test slopes to identify instability. Shooting cracks or mini avalanches on test slopes is a good sign that wind slabs are reactive. Ahtanum Meadows picked up 5-7 inches of snow with some moderate winds on Monday. It was likely just enough to form small wind slabs. While most avalanches would be small, travel cautiously in extreme terrain where small avalanches can have significant consequences. These lingering slabs may have formed over weak snow surfaces and slick crusts and still be easy to trigger.

    (3/18/2022)

    You could trigger small wind slabs like this example on Monday. Notice the corniced ridges pointing to the wind loaded slopes.

     

    Photo: Andrew Kiefer

  • Loose Wet

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

    In areas with fresh snow over slick crusts, small wet loose avalanches will become more likely as the sun warms southern aspects in the afternoon. Rollerballs and wet snow surfaces are the first signs of wet loose avalanche problems. These avalanches often initiate from steep rocks or trees shedding snow onto the slope below. While there isn't much snow over the crust, these avalanches could slide a long way on the slick crust if the slope is steep enough. Consider moving to shady slopes or lower angle terrain if you start noticing the snow surfaces beginning to rollerball in the sunshine. 

    (1/28/2024)

    Small wet loose avalanches shedding off cliffs in the sun. 

    Photo: Katie Warren

Avalanche Discussion

Another 1-3 inches of snow could fall in East South overnight and into Tuesday, with a chance of a sunny afternoon. The recent snow may have improved travel conditions, and now there might be enough to keep your snowmobile cool, but it probably isn't enough to leave the traction devices for slick surfaces at home yet. Open creeks, avalanche debris, and low snow cover will still complicate your travel plans.

We are still assessing all the impacts of the storm and the natural avalanche cycle. But we expect a significantly stronger snowpack exists throughout the zone now that temperatures have cooled. On Friday, in nearby East Central, I found widespread surface hoar and an inch of weak, faceted snow above 5700ft on the Early February Crust. These weak surfaces make for good sliding surfaces, and wind slabs or very small storm slabs may take longer to heal than normal. Use test slopes and quick hand pits to observe how the new snow reacts. If it slides easily, avalanches are more likely. 

The snowpack has endured a beating over the past week with several inches of rain and warm temperatures. Reports of new large and very large avalanches from Ahtanum Meadows, Crystal Mountain, and East Central flowed in almost daily from January 21st through February 1st, when temperatures finally dropped below freezing. We are still looking for old crowns and avalanche debris to understand the full extent of this warm, wet storm and prolonged avalanche cycle. If you find evidence of an avalanche that we haven't logged in our avalanche observations, take a photo and let us know by submitting a public observation! Even if you don't see any avalanches, we'd love to hear about what you did find out in the mountains, and it helps shape a more accurate avalanche forecast. 

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