Boletín de aludes

West Slopes North

Northwest Avalanche Center
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Peligro de aludes

Wed
Alta montaña
4 · Fuerte
Límite del bosque
4 · Fuerte
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

Large natural and human-triggered avalanches that could bury and kill you are expected with the 2-3 feet of storm snow that we'll likely see by the end of the day Tuesday.  This is going to be a snowy and windy day, so play it safe by steering around steep slopes, and take care to avoid traveling beneath large overhead avalanche paths as well. 

Problemas de aludes

  • Storm Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Very Likely
    Tamaño
    2–2.5

    Many of us are looking forward to the first larger storm in a while, but stay conservative while the storm's still here, as avalanche activity will be elevated.  During this storm, stay off steep slopes because it's very likely that you could trigger a large avalanche. Natural avalanches could also occur, with the possibility of a natural avalanche cycle during the day, meaning it'd be wise to steer around lower-angle terrain beneath large slopes as well. 

    We expect most avalanches to fail within or just beneath the new storm layer, which may be 1-3 feet deep depending on time of day and location. A small warming trend happening early morning means that the snow could be slightly upside-down, with a subtly heavier layer sitting on lighter snow beneath. This usually equates to a more reactive snowpack. At higher elevations and where wind has more of an influence, avalanches could be larger and more reactive.

    You could be out searching for signs of instability, like cracking, whumphing and recent avalanches, but there's enough of a large storm input during the day that you don't need to search out signs of instability - it's one of those days where it's best to just steer clear of avalanche terrain and let the storm run its course. 

    (2/6/2023) Small slabs failing with ski cuts on steep slopes on Monday, which we expect to grow much larger and more dangerous on Tuesday. 

    Photo: Lee Lazzara

Avalanche Discussion

This is the first time in a while that tree well and deep snow immersions will probably be a hazard. This is very important to take seriously when we get large snow dumps, as you could easily die from it. Other things to keep on your mind on Tuesday are lower elevation concerns like shallowly buried hazards, holes in the snow, and a moist snowpack, where small amounts of wet loose activity and rollerballs could occur. 

There is a small chance that avalanches could fail on weaknesses found within about a foot of the old snow surface at about 5000ft and higher. The faceted layer that we've been looking at, near the MLK crust, is not consistently present in many areas, so we don't expect to see too many avalanches stepping down to that layer, although there may be a few. The pit photos in the media gallery show the large variability in crust layering, and explains why we have more concern in some areas than others, due to the differing burial depths of the MLK crust. 

We've seen an abundance of smaller storms in recent days, with a few inches of snow falling here and there, and plenty of wind to redistribute the snow. A thicker layer, around a foot, fell over the weekend, but the snow was heavy and temperatures were warm. Not many avalanches were reported, aside from some wet loose at mid to lower elevations. On Monday, a few inches of snow was redistributed with strong winds, and small reactive slabs formed in specific areas according to one observer. Other observers nearby reported the small slabs were stubborn. In general, there's been a lot of variability in the snowpack even within a small area. Once we add a lot more snow and wind we expect see plenty of avalanche activity, but there are so many variables incoming and already on the ground that it's tough to tell exactly how Tuesday will play out. 

 

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