Boletín de aludes

Stevens Pass

Northwest Avalanche Center
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Peligro de aludes

Fri
Alta montaña
3 · Notable
Límite del bosque
2 · Moderado
Bajo el límite
2 · Moderado
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Desactualizado: este boletín caducó 6 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

The snowpack is still adjusting to recent heavy loading from rain, wind, and snow. Dangerous conditions linger in the alpine where you can trigger large avalanches in wind drifted snow. At lower elevations, non-avalanche concerns like firm and slick surfaces, open creeks, and downed trees may be your biggest hazard. 

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    2

    At upper elevations, strong winds and significant snowfall from the past 3 days created thick and reactive slabs. Cornices also grew during the storm and could fall on slopes below acting as huge triggers. Pay attention as you transition into wind affected terrain, and look and feel for sudden changes in snow surface texture and hardness. Watch for clues of instability like shooting cracks and collapses. Avoid slopes with similar characteristics to those where you see recent avalanches. Minimize exposure to overhead hazard and steer clear of cornice formations. To reduce your risk, seek out supported terrain away from wind loaded slopes 35 degrees and steeper. 

    (1/12/2021) Numerous crowns from natural slab avalanches on the southeast slopes of Rock Mountain near 5400ft.

  • Loose Wet

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–2

    Although the wet avalanche hazard already peaked, concern for loose wet avalanches still lingers at lower elevations. Look for signs of instability like rollerballs, pinwheels, and recent fan-shaped avalanches. With all the recent precipitation, keep glide avalanches are your radar as well. They are difficult to predict, but cracks, which usually form first, are a good indicator. Watch for deep cracks in the snow in steep areas, usually with ground visible at the bottom. Stay off slopes where you see these cracks or any slopes with similar characteristics. Sunshine on Thursday could be a factor driving loose avalanche concerns. But, the potential for loose wet avalanches will be limited anywhere you encounter a firm and frozen crust at the surface.

Avalanche Discussion

A hazardous atmospheric river event (observed category 3-5 AR along the WA and OR coast) delivered almost 5in of water to Stevens Pass January 11-13. Not surprisingly, a widespread natural avalanche cycle occurred as a result. Observers Tuesday found wet and dry snow avalanches in many areas. One very large avalanche ran naturally in the Wellington slide path, with a nasty debris pile gouging through the snowpack to ground. Most dry slab avalanches seemed to run on the new old interface from Jan 11th about 1ft below the surface. Snowpack tests also revealed a poor bond at this interface. As precipitation tapered off early Wednesday, strong cooling occurred with a 10-15F degree drop in temperatures. Many areas now have a firm and frozen crust with slick and challenging travel conditions. Despite the cooling, the snowpack is still saturated below the frozen crust and draining significant water from all the rain. Snow and avalanche conditions are unusual following such a dramatic storm event like this. Continue to build in a wide margin for error, especially at upper elevations where recent observations are limited. 

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources. Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

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