Bulletin d’avalanche

West Slopes Central

Northwest Avalanche Center
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Danger d’avalanche

Wed
Alpin
4 · Fort
Limite forestière
4 · Fort
Sous la limite
3 · Marqué
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Points saillants

A large storm will dump around two feet of snow by the end of the day and we can expect to see natural and human-triggered storm snow avalanches large enough to bury and kill you. If you get into the backcountry, stick to lower-angle terrain, making sure to avoid traveling beneath large steep slopes as well. 

Problèmes avalancheux

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Very Likely
    Taille
    1.5–2

    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.  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 6 inches to 2 feet deep depending on time of day and location. A 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. 

    Storm slabs like this may be easily triggered on Tuesday. This is a small test slope. Avalanches will probably be deeper than the one in this photo. 

    Photo: Public Observation

Avalanche Discussion

Small wet loose avalanches and rollerballs may come down at lower elevations, where shallower amounts of new snow are present, and the snow is moist. Neighboring zones are seeing an inconsistent weak layer of snow near the MLK crust. This layer is of greater concern in areas where it's more shallowly buried, about 1ft deep.  You may be able to find it in the West Central zone. Circumstances where you might encounter patches of this weak layer are mainly above 5000ft on shady aspects. The layer 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. 

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 slightly thicker layer fell over the weekend, but the snow was heavy and temperatures were warm and there were reports it bonded well to underlying layers.  Once we add a lot more snow and wind we expect to see plenty of avalanche activity, but there are so many variables with the new storm and with what's already on the ground that it's tough to tell exactly how Tuesday will play out. 

Régions couvertes