Boletín de aludes

West Slopes South

Northwest Avalanche Center
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Peligro de aludes

Sat
Alta montaña
4 · Fuerte
Límite del bosque
4 · Fuerte
Bajo el límite
3 · Notable
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Desactualizado: este boletín caducó 5 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Very dangerous avalanche conditions will persist into Friday morning especially near and above treeline across the West South zone. Natural avalanches will occur as continued snowfall and strong winds pummel the mountains. This is one of those times to stay well away from anywhere an avalanche could start, run, or stop.

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Very Likely
    Tamaño
    2–3

    Strong ridgeline winds will continue to rake the West South zone, easily transport snow, and likely form stiff wind slabs on the lee sides of ridges. As the wind loading event continues Friday, expect natural wind slab avalanche to occur. With all the new snow, many of these slides could grow very large and destructive as they descend. These may not be the normal soft wind slabs we sometimes get in the Cascades. These could be thick, hard, and dangerous. Fortunately, the solution is simple. Stay off of and out from under any steep open slope. This includes considering the terrain well above your head. Go around the tracks and runouts to very large avalanche paths that end down in the forest. Let this storm play out from somewhere well away from avalanche terrain.

    (1/6/2022)

    Blowing snow and blizzard like conditions at Crystal Mt Ski area Thursday. Strong winds easily drifted snow on any open slope. 

    Photo: Rikki Dunn

  • Storm Slabs

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

    At lower elevations, ample storm snow stacked up on Thursday and will continue to fall into Friday. Changes in temperatures, precipitation rate, wind speed, and even snowflake type formed layers in the new snow that could produce large and deadly avalanches. These layers need time to adjust to the rapid load. Avoid any open slope greater than 35 degrees at lower elevations. 

    Below the rain-snow line, you could encounter loose wet, wet slab, and glide avalanches. Any of these wet problems could produce large avalanches to an unwary traveler down in the forest. If you are out for a walk in the woods, avoid steep open slopes and don’t linger in openings where avalanche terrain sits above your head.

    (1/6/2022)

    Example: This 2' deep avalanche occurred on Dodge Ridge near the Summit West ski area Thrusday. Many large and very large avalanches were reported by the DOT. 

    Photo: WSDTO SCR

Avalanche Discussion

Nearly all of our weather stations in the West South zone are experiencing issues at the moment. Power outages and communication connections severely hampered our ability to collect information. However, what we do know is simple. A very potent winter storm dropped more than 4” of water (3-5’ of snow) at Paradise with slightly lesser amounts near Crystal, White Pass, and Mt St Helens. Crystal Mt Ski Patrol reported more than 2 feet of new snow in the last 24hrs. Avalanche observations are limited, but at least one large natural avalanche was reported in the Crystal area and multiple slides occurred along Hwy12. A pair of very large avalanches were reported through the seismic network at Mt St Helens. These avalanches released during the early morning hours on Thursday on the N and E sides of the mountain. 

The storm isn’t over yet. We expect significant snow Thursday night into Friday morning. You could see additional rounds of natural avalanche activity. In the nearby Snoqualmie Pass zone, avalanche professionals reported some slide paths avalanching multiple times during the storm. Look for the peak danger first thing Friday morning. As precipitation tapers and the storm shifts north, avalanche danger will very slowly subside. But, don’t forget, this was a huge change for the snowpack, and the mountains will need time to adjust. 

With all the new snow, snow immersion suffocation (SIS) and treewells present a very real hazard to any traveler. Keep your partners insight.

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