Bollettino valanghe

West Slopes North

Northwest Avalanche Center
Vedi sulla mappa

Pericolo valanghe

Thu
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
Open full map
Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

It is likely that you can trigger a large, deep avalanche on steep upper elevation, unsupported slopes in the backcountry on Wednesday. Avalanches could break as far down as the old snow surface and be large enough to bury, injure or kill you, so consider the consequences of triggering an avalanche if you choose to travel in these areas. Wet loose avalanches could occur, possibly on southerly slopes if we see the sun, or maybe all areas if low clouds persist. 

Problemi valanghivi

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1.5–2.5

    Large avalanches requiring a trigger failed around three feet deep in the Baker backcountry on Tuesday. There were also a few storm interfaces around 6 inches and a foot down, but they are expected to heal quicker than the deeper avalanches. The deeper ones occurred just above a crust, probably involving a weak layer. This problem is not easy to identify and avoid. We currently know little about it after the large storm which just deposited 3 feet of snow at upper elevations.

    You're most likely to trigger one of these large, deadly avalanches in the upper portions of near treeline and above treeline areas.  Expect them to occur on large, steep, unsupported slopes. Until we know more about this weak layer, consider avoiding these unsupported slopes at angles greater than 35 degrees.  An unsupported slope refers to a slope that rolls over into steeper terrain, without an abrupt transition to lower angle terrain beneath that steep rollover within a short distance. Pay attention to the usual signs of unstable snow such as cracking and whumphing, but these indicators are probably not precursors that you will find before triggering one of these deeper avalanches. 

    (3/15/2022)

    A large storm slab avalanche, running on the old snow surface approximately 3 feet down on Hemispheres.

    Photo: Adam Ü

  • Loose Wet

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

    Wet loose avalanches will remain limited to the new snow layers. Snow finally fell in below treeline areas Monday night onwards. There is around a foot of snow at the upper portions of below treeline elevations, and the little snow which is there could easily slide on the old, hard snow surface. More snow as we gain elevation could mean wet loose avalanches might run deeper, up to large in size, but probably only entraining the upper portion of the new snow layer which gets moist, up to the top foot or so. If skies clear expect to see avalanches mainly on south-facing slopes. If low clouds persist, they could trap moisture and heat, resulting in wet loose avalanches occurring on more aspects than just the southerly half of the compass.

    If you notice snow surfaces getting moist, pay attention to rollerballs or small avalanches coming down, or whether you find it easy to trigger one yourself. If this is the case, steer clear of steep slopes in locations where you find the moist snow conditions, shifting to other aspects or sticking to lower angle terrain.

    (3/13/2022)

    Wet loose avalanches that ran with ski cuts in the Swift Creek drainage area of the Baker backcountry on Sunday. With more new snow since then wet loose avalanches could be larger.  

    Photo: Public Obs

Avalanche Discussion

The storm snow is now settled to about 3 feet at 5000ft in the Baker backcountry. There's about 2 feet at 4200ft, and it rapidly drops beneath that elevation. Monday night, snowfall started at about 3000ft, coating the old, well transformed lower elevation snow. It is suspected that other nearby areas along Highway 542 hold less snow than the snow totals we're getting from the weather station at Heather Meadows. If you travel to areas with a thinner new snow layer over the old snow, you might encounter pockets of reactive wind slabs. Stick to smaller slopes and pay attention to signs like cracking before heading out onto larger slopes. 

Regioni coperte