Boletín de aludes

East Slopes North

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 2 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

You could trigger avalanches in areas where recent winds drifted snow into stiffer slabs. Confined alpine features and steep slopes below ridgelines are likely places for this lingering problem. Consider steering around these features and approach complex, wind-exposed terrain slowly and conservatively. Cracks shooting from your equipment or recent avalanches are signs to choose lower-angle slopes. 

Problemas de aludes

  • Wind Slabs

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

    While winds and precipitation will take a break on Tuesday, lingering wind slabs could still be reactive. Visual clues, such as cornice formations, textured surfaces, or cracking in stiff surface snow layers, can help identify wind-loaded terrain.  Consider steering around steep slopes where you identify these wind slab features. Other ways to avoid triggering avalanches are to avoid typical trigger points, such as convex features, unsupported slopes, and confined gullies.

    We don't expect avalanches to be large, but even a small avalanche could carry high consequences in complex terrain.  Recent avalanches, collapses, and cracks shooting through the snow indicate unstable snow. Before traveling on larger slopes, use small features and quick tests to see how easily the snow slides.

    (12/25/2024)

    A small skier-triggered wind slab on a convex feature, about 10" deep, size D1. Delancey Ridge, 6,500ft, S

    Photo: Will Govus

Avalanche Discussion

Expect clearing skies and a chilly night in the zone, with the chance of some sun on Tuesday. The cold temperatures will likely limit any wet loose avalanches from sun-induced warming, but watch those steep rock faces for isolated rollerballs. More importantly, another storm is scheduled to arrive by Tuesday night, and the brief, clear, cold weather could weaken surfaces or develop a surface hoar layer. So, look closely at Monday's snow surface, as it might be Tuesday's weak layer. 

While most observers report isolated wind slabs in the likely places, there have been a couple of observations of deeper instabilities over the weekend. A skier triggered an avalanche near Cutthroat Lake on a southerly, unsupported slope at upper elevations, not far from the ridgetop. This slide broke ~70cm deep on what we expect is the Solstice Crust. On Delancey Ridge, an observer reported signs of instability at lower to middle elevations on a southeast aspect. They reported a collapse at 4,800ft and then sudden results in multiple compression tests ~70cm below the surface on the Solstice Crust at 5,300-5,680ft. The height of the snow there was 168cm.

Snow totals throughout this week are between 2-4 feet above 4000ft. Below that, there has been significantly less accumulation, and the snowpack is moist from warm temperatures and light rain. Despite the recent warm temperatures, there's decent coverage at lower elevations and in the eastern mountains. On Thursday and Friday, observers in the Twisp River drainage found a relatively strong snowpack, though still shallower than at the Cascade crest. There was 70-100cm of snow on the ground near 3,000ft, and depths increased with elevation. In the foothills and eastern portion of the zone, you may find more weak layers than at the Cascade crest. Pay attention to red flag signs of instability, such as whumping collapses, and consider digging down to identify potential weak layers. The Loup Loup area has a relatively robust snowpack compared to many years, though still shallow compared to further west. 

You can contribute to the avalanche forecast. Please let us know what you see in the mountains by submitting an observation. 

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