Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

Wed
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

There's a chance that you may still be able to trigger an avalanche at upper elevations. Look for signs of instability like cracking as you travel. With a recently buried layer of surface hoar, it's a good idea to ease into the terrain and evaluate each slope separately. 

Problemi valanghivi

  • Wind Slabs

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

    Watch for signs of instability like cracking and recent avalanches. Leeward sides of ridges and steep, unsupported terrain may be the most likely place to trigger a small slab avalanche. Avalanches could be 1-1.5ft deep, especially in areas that have received wind loading in the past few days. Buried surface hoar is 'spatially variable' in that you may find it on some slopes but not others, even if they are the same aspect and/or elevation. You can dig many quick tests and look for easy, clean failures as an indicator of the weak layer. If you find it, choose lower-angle terrain. 

    You may also be able to trigger small loose slides, on steep slopes. Stay on guard if the snow slides easily, or you observe rollerballs and moist sticky snow.

    (12/11/2022) Wind producing a lenticular cloud and wind effected surfaces on Mt Mastif Photo: Josh Hirshberg

Avalanche Discussion

We've received a flurry of observations from the Stevens Pass area. Observers on Sunday found fast and clean shears beneath the new snow, 8" down on a shaded, sheltered northerly aspect near Arrowhead.  The failure layer often involved buried surface hoar, sometimes under a thin crust. They also observed some wind-affected snow in the Henry Creek clearcut, but slabs were generally unreactive. Warm temperatures have substantially helped to settle the new snow. Observers reported a layer of surface hoar, buried on December 8th, about 8"-18" below the surface. They found a few areas where previous wind drifting had overlaid slabs on this layer. 

Layers of weak snow and crusts were buried by a series of storms in mid to late November. This layer is now near the ground, and has been observed to be gaining strength and rounding. These older layers generally haven't been a problem for avalanches in this zone as much as in the East Central zone, though it's something to consider, especially in true alpine terrain. Remember, the snowpack may still be hiding shallowly buried hazards of rocks and stumps, especially at lower elevations. Let us know what you see by submitting an observation!

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