Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

Mon
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
Non aggiornato — questo bollettino è scaduto 8 months ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Moderate winds and snowfall could build stiff slabs below ridgelines. You can reduce your risk by steering around areas with textured, wind-drifted snow on steep terrain. The modest precipitation amounts should keep avalanches in this drifted snow small, but could still ruin your day if you're carried into trees or rocks. 

Problemi valanghivi

  • Wind Slabs

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

    Actively blowing snow or cornice formations help you identify suspect leeward slopes. Steer around steep slopes where you find deep, textured drifts. You can use small test features to see whether the snow cracks or triggers a mini-avalanche.  Hand pits are another great way to quickly assess the bond to the old snow surface across many different slopes as you travel. If the block of snow slides easily, it is more unstable. Cracking or easy shears in hand pits should point you toward lower-angle terrain as a safer option. We expect wind slabs to involve only the new snow, limiting avalanche size. However, we have minimal information from upper elevations, so there is a fair amount of uncertainty in alpine areas. If you find drifted snow deeper than 8-10", expect that avalanches could be large enough to bury you. 

    (3/20/2022)

    Steep, rocky, lee slopes, like in this photo, are prime locations for wind slabs. 

    Photo: Ryan Minton

Avalanche Discussion

Cooling temperatures and a return of snowfall to our lower elevations will be a welcome shift in the weather pattern for Sunday. It's not a lot of snow, but hopefully we end up with 4-6" to cover the myriad of breakable crusts at mid and lower elevations. While we anticipate a decent bond with moist, old snow surfaces, we'll have to wait until tomorrow to confirm. At upper elevations, there could be some preserved weak surfaces that will be buried. These would probably exist at the very upper extent of our forecast, but something to keep in mind if you're headed into alpine areas. 

There are a few notable crusts in the snowpack, aside from the current surface crust formed over the past few days. The December 24th crust is buried about 1' deep and can be found up to around 5500ft in elevation. A thicker crust from December 18th is 2-3' deep, and we expect it exists at most elevations, although we don't have information to confirm it extends past 6000ft. These crusts haven't shown any signs of instability, but they are useful markers for tracking the snowpack.

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