Bollettino valanghe

West Slopes North

Northwest Avalanche Center
Vedi sulla mappa

Pericolo valanghe

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

In sintesi

Avalanche activity is expected to peak overnight when another 6 inches of snow falls, and human triggered avalanches are likely on Sunday. Avalanches could fail in the recent storm snow, 1-2ft deep, and this is a day to avoid stepping out onto steep slopes and to stick to lower angle terrain. Warmer temperatures may cause small wet avalanches at lower elevations, and any sun breaks may result in wet activity on south-facing slopes. 

Problemi valanghivi

  • Storm Slabs

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

    There was more avalanche activity than expected on Saturday, and several human triggered 6-12 inch slab avalanches were reported in the Baker backcountry (OBSERVATION, OBSERVATION, OBSERVATION) The new snow was heavier over an underlying lighter layer (upside down). With another 6 inches or so of snow Saturday night, you can expect to see continued avalanche activity, which may fail a foot down or deeper in the recent snow layers. On Sunday, it is likely that you can trigger an avalanche. Wind loaded slopes will probably be more reactive, but all steep slopes are suspect. 

    Whumphing, shooting cracks, and recent avalanches are all signs you'll probably trigger an avalanche if you head into steeper terrain. Some shadier or upper elevation locations may harbor buried surface hoar or weak facets left over from New Year's. If you dig down you may find these layers, probably about 1.5ft beneath the surface on Sunday. Whether they exist or not, we've had enough confirmations from Saturday that new, heavier snow lies over weaker or lighter snow and avalanches were triggered. It's likely that you'll find the same thing on Sunday. As you increase in elevation and change aspects you can expect to find different snow layerings and maybe greater chances of triggering avalanches. 

    Avoid traveling on slopes steeper than 30° on Sunday, and spend your time in lower angle terrain. The further south you travel in the zone the greater the snowfall amounts will be.

    (1/4/2025) Crown of a larger avalanche, human triggered, in the Baker backcountry on Saturday. 

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    Rollerballs or possibly wet avalanches running naturally or with a human trigger could occur on Sunday. Avalanche activity will likely remain limited to the newer and softer surface layers at lower elevations, which may creep into mid elevations later in the day. Consistent snow cover to produce avalanche activity starts around 3000-3500ft. 

    If any sun pops out in the afternoon, expect to see rollerballs and then wet loose avalanches on steep south-facing slopes. We're not sure if you'll see this on Sunday, but we expect a lot more sun and an intense uptick of south-facing wet avalanche activity on Monday. 

    If you initiate rollerballs or small surface slides in moist snow, or notice any natural wet avalanches fanning out, avoid traveling on steep nearby slopes and avoid lower angle terrain beneath those slopes as well. 

    (11/25/2024)

    Rollerballs may be a precursor to wet loose avalanche activity. If you start seeing them, start thinking about the possibility of subsequent wet loose avalanches. 

    Photo: Irene Henninger

Avalanche Discussion

Weak surface layers that formed during the storm break over New Year's may have been destroyed at lower elevations with the warmer temperatures. In higher alpine terrain we usually have stronger wind and weak snow is often scattered or destroyed before more snow falls. A few of the observations from Saturday leads us to believe that pockets of persistent weak layers, now buried 1-1.5ft below the surface, may still exist in areas of the mid and upper elevation band. More of a load Saturday night may result in natural activity which could avalanche on this layer, wiping it out, but a lot of uncertainty exists regarding how widespread this problem is, how reactive it may be, and how long the problem will last for. This problem may be more pronounced in areas that tend to stay cooler like Canyon Creek or further east in the forecast zone along Hwy 20. 

If you make it into the backcountry on Sunday, please share what you saw with us. It'd be particularly helpful for us to know if you saw or triggered avalanches, or even moreso, if you didn't. You can submit an observation HERE, or by using the Avy app. 

Regioni coperte