Bollettino valanghe

West Slopes North

Northwest Avalanche Center
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Pericolo valanghe

Tue
Alta quota
4 · Forte
Limite del bosco
4 · Forte
Sotto il limite
4 · Forte
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In sintesi

Very dangerous avalanche conditions are present as a large storm dumps several inches of snow on us overnight and during the day. Warming temperatures will exacerbate the problem. Avoid all areas of avalanche terrain on Monday, including flat areas beneath large avalanche paths as large avalanches are very likely. 

Problemi valanghivi

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Very Likely
    Dimensione
    1.5–3

    High avalanche danger exists on all slopes loaded with over a foot of new snow.  Areas where wind drifted the snow into thicker slabs are more prone to sliding.  Sunday night 1.5 inches of water is forecasted to fall, which might mean over a foot of snow at upper elevations, on top of the foot we received Saturday night and Sunday. During the day 2 more inches of water will fall, around 2 feet of snow at upper elevations. Meanwhile, many areas will see strong winds influencing the snow.  

    Monday is a day to avoid avalanche terrain, as very large avalanches could run from above, even into below treeline areas. Natural and human-triggered storm slabs are more likely during periods of intense snowfall and rising snow levels. Don’t ignore obvious signs of instability like shooting cracks, whumphs, or recent avalanche activity.  Approach any steep slope with caution and remain aware of terrain above you. 

    Example of storm slab avalanche. It is very likely that you could trigger a large or very large slab avalanche on Monday. Photo: Pete Durr, USFS Backcountry Ranger

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Very Likely
    Dimensione
    1.5–3

    Expect an increase in wet loose avalanches as temperatures creep up throughout the day. Freezing levels are forecasted to rise to 5500ft by the evening. Rain will quickly compress the new snow, in addition to making surfaces moist. It will affect the top couple inches of snow, or much deeper at lower elevations. 

    Depending on your elevation and what time of day it is, you will find varying amounts of the wet loose avalanche problem running in the moist snow. First thing, it will exist at lower elevations, but as temperatures warm you'll notice snow getting heavier and rollerballs starting to kick off at higher elevations. This is another reason to avoid steep slopes and the areas beneath them on Monday. 

    (2/27/2022) Slopes were getting moist as temperatures increased Sunday. Tiny rollerballs began running from our tracks. This was not an avalanche concern yet, but I was already paying attention to it and monitoring for when the rollerballs became more frequent and picked up more mass. At that point I'd steer clear of steep slopes. Photo: Irene Henninger

Avalanche Discussion

A variety of conditions were encountered Sunday depending on where you traveled. I went to the Canyon Creek area, where a treed ridgeline showed obvious signs of drifting and snow redistribution, however most areas we traveled were not wind-affected.  Wind transport was a major driver for avalanche concerns in the Baker backcountry, and there were reports of small natural wind slab avalanches in the morning. Later on, thick drifts were stubborn according to some backcountry users.

Weak snow surfaces could exist beneath Saturday night's snowfall, as I found in my pit on Sunday. Strong winds leading into the storm may have destroyed some of these weak layers, but they might still exist in sheltered areas. Another 2 or 3 inches of water, strong winds, and increasing temperatures could swing the avalanche danger extensively in the next 24 hours. A lot of uncertainty exists with the weather factors driving this storm, so it's best to play it safe and stay out of avalanche terrain while the storm dumps. Stick to lower angle slopes where you can still have a good time. 

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