Bollettino valanghe

West Slopes North

Northwest Avalanche Center
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Pericolo valanghe

Sat
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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In sintesi

Recently formed slabs of wind-drifted snow will be the greatest avalanche hazard.  Steer around steep terrain holding denser snow. You are most likely to trigger a slab on unsupported slopes like those above or around cliffs, or on convex breakovers. Dropping temperatures, tree wells, and deep snow will be additional hazards to plan for on Friday. 

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    We are coming to the end of an active weather pattern and transitioning to a period of much colder, more stable weather. The widespread wind slab formation observed on Thursday will end in most locations, so we will be left to deal with stubborn, day-old slabs. With a wind shift to the northeast a few areas (notably north and east of Hwy 542) could see another round of slab formation on south and west aspects.

    Use the standard clues like cornices and wind-scoured surfaces to identify the loading pattern around you. Hand shears and test slopes on small, wind-drifted features can give you a sense of slab reactivity. While they will be harder to trigger on Friday, you can still find a wind slab, especially on very steep unsupported slopes or around rock buttresses. Fresh slabs from northeast winds will likely be more reactive. You might even see a few natural avalanches as well.

    (1/11/2024)

    A small but deep wind slab avalanche in the Baker BC. It was unintentionally triggered on a southeast aspect at 5400'. (HS-ASu-R1-S).

    Photo: Elias

Avalanche Discussion

Widespread wind transport from strong westerly winds was observed on Thursday. Multiple wind slab avalanches to D1.5 were triggered, generally on slopes with an easterly aspect. Observers were able to get shooting cracks pretty much at will in wind-drifted terrain, especially in the morning when slopes were actively loading up and slabs were at peak instability.

While recent wind slabs are the type of avalanche you are most likely to encounter, you could still trigger a slab avalanche in wind-sheltered terrain. A layer of facets overlying the 12/30 melt-freeze crust is now buried 3-5’ deep (or deeper!) in many locations. Avalanche activity associated with this interface is decreasing, but on Wednesday morning, control work near Mt Baker Ski Area pulled out a slab avalanche 3-5’ deep. Given the depth, it probably failed at the same 12/30 crust-facet interface. 

Calmer conditions heading into the weekend will open the door to the bigger, steeper, and unsupported terrain where you might find one. Use caution approaching big slopes in the coming days and get a handle on snowpack structure and recent avalanche activity before considering more complex terrain.

Regioni coperte