Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

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

In sintesi

Warming of steep, sunny slopes will be the main concern on Friday.  Look for signs of instability such as rollerballs and wet, sticky snow during the middle of the day. On high shaded slopes near ridgelines, use caution near areas of firm or hollow sounding snow.

Problemi valanghivi

  • Loose Wet

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

    Strong sun will melt down surface crusts quickly on steep, south facing slopes. Look for signs of warming instabilities such as rollerballs, or moist sticky snow overlying cooler, unconsolidated dry snow. Be cognisant before entering any steep, committing features where the consequences of getting caught in a small entrainment of wet snow could be higher. There may not be natural wet slides on Friday, but if you are riding in the wrong place at the wrong time, you could trigger one of these avalanches. If the snow surface is crusted over and refrozen, then the danger of triggering these slides has likely already passed. 

    Example loose wet avalanches on a steep southeast aspect of Rock Mtn.

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    1

    Wind slabs can be found in pockety distribution around the compass.  Observers noticed plumes on Wednesday indicating wind transport from South and East winds. You may find these slabs on any exposed slopes, but are most likely to be a problem on very steep, shaded and unsupported slopes. These are becoming less and less reactive with time, though you may still find the sweet spot and trigger one. Wind slabs may be thickest near ridgelines in the alpine zone.

    Identify recently loaded features through visual clues such as textured surfaces and plump looking pockets behind terrain features. Be alert of cornices that may chunk off with warm sunny temperatures. If you observe signs of instability such as shooting cracks, be sure to avoid steep slopes in the vicinity. 

    (12/2/2020) South-easterly winds continued to load NW aspects at the top of the Swath's start zone on Tuesday.

Avalanche Discussion

Plumes were observed coming off ridgelines in the area on Wednesday with constant drifting and transporting of snow at upper elevations. No obvious signs of instability were observed, but the structure of firm slabs over weak snow existed. On Tuesday, an observer reported a large collapse on a windslab below treeline near Skyline Ridge. In the eastern edge of the zone, and nearby East Central zone we are still keeping our guards up due to surface hoar that was observed prior to the last snowfall event. Otherwise, a snowpack with a favorable hardness profile and good stability can be found.  

While the snowpack around the Pass is impressive for the beginning of December (40-60”/105-150cm), plenty of early-season obstacles still exist. Watch for open creeks, buried logs, and numerous small trees that may block your path.

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.

Regioni coperte