Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

Wed
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 6 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

The snowpack is primed for human triggered slab and loose avalanches. At mid and upper elevations, slabs could be very large and deep. Steer around steep open slopes while the snowpack adjusts to the heavy new load. Look for signs of instability, and choose conservative terrain, staying off of and out from underneath large open slopes.

Problemi valanghivi

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    2–3

    Steer around open slopes 35 degrees and steeper until the snowpack has a chance to adjust to this hefty new load. On Monday the storm came in with warming temperatures, overlaying a slab on low density snow underneath. Strong winds and convergence in the evening may tip the scales at upper elevations and create natural avalanches overnight on Monday. Lingering instabilities on Tuesday should hold your attention. Any avalanche triggered in the recent snow could step down to crusts from New Years Day, 12/29, or a deeper to the crust from 12/21. The 12/21 crust may be found over 6ft deep, with weaker, dry snow just above it. With all of the uncertainty, it'll be best to stay off of slopes steep enough to avalanche. As you travel, take a look at which layers are failing and consider the consequences of even small pieces of steep terrain.  Assess for shooting cracks and whumphing collapses. As you ascend in elevation or travel into wind affected terrain, remember slabs will be more cohesive, and potentially deeper and more destructive. 

    Loose dry avalanches may run easily on Tuesday. Look for these fan-shaped slides that start from a point (also known as point releases). In big, steep terrain these could entrain lots of snow, and create larger avalanches. 

    (1/2/2021) 200ft wide avalanche on a SW aspect of Round Mountain in the Hwy 2 Corridor.

Avalanche Discussion

We’re more than 7 days into a prolonged storm cycle at Stevens Pass. Snow continues to pile up, especially at mid and upper elevations. As the storm totals grow so does our uncertainty with recent crust layers. Any avalanche has the potential to entrain additional snow, grow larger and become destructive.

On Monday, Josh Hirshberg found minimal slab structure below treeline, but some cracking at 5,300ft on a SW aspect in very steep terrain. He also observed recent D2 wet debris at 3,900ft that came from higher up. On Sunday, avalanche professionals observed a large (D2) avalanche off a southeast aspect in Moonlight, just east of the pass proper. Ski Patrol had good results with ski cuts, and reported a natural cycle of soft slabs overnight prior to Sunday. On Saturday morning, WSDOT avalanche team triggered some large slides down to the 12/21 crust. A few reports also came in on Saturday of slides being triggered on a suncrust from 12/29. These were on South aspects at 5,000ft, and one was 200ft wide on nearby Round Mountain. In short, there are plenty of recently buried weak layers, and they all demand respect. Even if the snow felt 'right side up' on Sunday, it may not be that way Monday, and the extra load is concerning for deeper crust layers. 

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources. Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

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