Boletín de aludes

West Slopes South

Northwest Avalanche Center
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Peligro de aludes

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

Lo esencial

Another day of rain will continue to maintain unstable wet snow and potentially dangerous conditions. With these difficult to predict wet slides, it’s more about the consequences of large powerful avalanches than if you can trigger one. So, stay off of steep open slopes and limit any time you spend underneath them.

Problemas de aludes

  • Wet Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    1.5–2.5

    It's easy to think after three days of rain in the West South zone, that the bulk of the avalanche hazard has passed. However, with so many layers in the snowpack prior to this storm and so much rain falling, we could experience several rounds of avalanche activity. You may see wet slab, glide, loose wet, or cornice avalanches. Sometimes blocks of snow may simply shed from steep rocky faces. All of these avalanches can be incredibly difficult to predict. While it may be hard for you to trigger any of these slides, you certainly don’t want to be under one if it fails. So, let the consequences of these often larger and more powerful avalanches shape how you travel. Stay off of open slopes greater than 35 degrees and minimize any time you spend traveling below them. With conditions like this, even traveling through the runout of an avalanche path brings more risk than normal.

    (12/24/2022)

    A large natural wet avalanche below treeline in Mt Rainier National Park. 

    Photo: NPS Rainier Rangers

Avalanche Discussion

It’s been a warm and wet Holiday weekend in the West South zone. Most areas received 2-4 in of precipitation since 12/23, and counting. How much of this fell as rain verse snow, freezing rain, and sleet depends on your location and elevation. However, at this point, significant rain has reached well into the above treeline bands. Photos from Paradise on Mt Rainier show rollerballs and runnels… clear signs of rain on snow. 

Observations were limited due to stormy weather and poor visibility over the past several days. So, we still don’t know the full extent of the damage. Even still, NPS rangers reported 2 larger natural avalanches at lower elevations near the Nisqually River. Other smaller loose wet slides were observed at Crystal Mt, Mt Rainier, and White Pass. Given that this rain fell on a very dry, cold, and layered snowpack we may hear of other slides that occurred during the brunt of the storm. 

Lowering snow levels after the cold front passes Monday will bring snow back to the higher peaks and ridgelines. In a few isolated areas, smooth pillow-like drifts may form by the end of the day. They shouldn’t pose much of a hazard. Simply identify and avoid these wind-loaded pockets. A much stronger cooling trend will be needed to finally put these wet issues to bed.

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