Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

Sun
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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In sintesi

The riding conditions will be amazing, but don't let powder fever take hold of your decisions in the mountains. Deceptively dangerous conditions are forming with a foot of new snow, strong wind, and multiple weak layers for the new snow to slide on. Slabs could be 10" deep and fluffy, or they could be 2.5ft deep ugly beasts. Take a big step back in your terrain, steering clear of steep, open slopes while instability peaks on Saturday. 

Problemi valanghivi

  • Storm Slabs

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

    New snow has been slowly stacking up during the week, and now we've got a one-two punch going into Saturday. With over a foot of new snow expected, it could be a spicy day. Instability may be blatent and obvious, or it may be more subtle...it's hard to say. In any case, it'll be enough to stress multiple potential weak layers in the upper foot or two of the snowpack. Most slides will likely run on or just above the most recent crust, and could be 10-16" deep. However, we know we have weak layers deeper down, so slides have the potential to step down 2.5ft deep on older, weak crusts. Look for activity to spike during periods of heavier snowfall. At mid and upper elevations, exposed areas will see continued wind drifting, which could create more cohesive and thicker slabs. 

    Avoidance of steep slopes is highly recommended, along with tight planning, teamwork, navigation, evaluation, and communication. Signs of instability could include long shooting cracks, whumphing collapses, or recent avalanches. 

    (12/2/2023)

    Example of a 2ft deep storm slab from earlier in the season.

    Photo: Zack McGill- Cascade Mtn Ascents

Avalanche Discussion

Here comes a nice looking storm that should deliver some beautiful cold powder. We've all been missing it this season, and are psyched to get out and sample the goods. However, ITS GOING TO BE DANGEROUS!!! We've got all the ingredients for slab avalanches with multiple potential weak layers. Even if you don't see obvious clues to instabilty, the snowpack should be treated as being highly suspicious until we as a community begin to get a handle on how this snowpack reacts. The weak layers are here with us through the weekend and are likely to produce avalanches well into the week as more storms keeping adding up. 

Over the past week, observers have been finding sudden and propagating failures with the crust buried around the Solstice. This layer has been about 12-18" down until now, and is made up of a decomposed crust at lower eleavtions. At mid and upper elevations its a decomposed crust but may have a slick, translucent crust with facets and/or surface hoar above or within. This structure is fairly widespread around the region, and is likely to play a role with larger avalanches as more snow adds up.

On Wednesday, we traveled to the north side of Lichtenberg and found about 5" of snow on a thin crust from 12/30. A thin layer of small facets and small surface hoar was found about an inch above the crust on shaded slopes at mid and upper elevations. On a south aspect at 5,800ft, the new snow wasn't bonding well to the slick crust. Tilt tests also showed that the newer snow was not bonded very well to the upper crust.

Travel conditions and coverage are still thin, but improving by the day. Continue to beware of hitting exposed rocks, stumps, and creek openings, especially at lower elevations. You can contribute to the forecast! Let us know what you found by submitting an observation HERE. 

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