Bollettino valanghe

Snoqualmie 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
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In sintesi

With more sunshine expected on Sunday along with slightly warmer temperatures, we may see more widespread loose wet avalanches than the last few days.  Watch for pinwheels or natural loose wet avalanches on very steep sunny slopes or below rock outcroppings as signs of increasing instability. 

Problemi valanghivi

  • Loose Wet

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

    Be suspicious of very steep sunny slopes without rollerballs or evidence of recent loose wet avalanches.  While these avalanches will likely be small,  don't let them catch you by surprise near cliff bands, or near other terrain traps.  If you find yourself sinking into wet snow deeper than your ankle or see wet avalanches, it's time to choose lower angle terrain or a different aspect.  Since this recent snow sits on a crust, some of these slides may run farther downhill than you expect.  Pay attention to the terrain above you and don’t linger under steep slopes basking in the sun.  As we inch closer to the spring equinox with a higher sun angle and longer days,  we'll start to expand the compass regarding loose wet avalanches. 

    While unlikely, if you see avalanches entraining deeper older layers, the problem has become larger and more dangerous.  If you observe bigger, gouging loose wet avalanches, stay off of and out from under all steep sunny slopes.

    (2/10/2022)

    Example: A small natural loose wet avalanche on a steep rocky slope. You may see similar slides Sunday. 

    Photo: Robert Hahn

Avalanche Discussion

The glass was half empty with more cloud cover than sun Saturday near and west of the Pass.  Much like Friday, cloud cover helped limit the sun's impact on the snow surface to varying degrees across the zone.  While there may be a thin sun crust in some areas, above 4500 ft you will generally find 4-6 inches of settling dry snow from March 2-3rd above a refreezing crust. 

Below this interface, the upper snowpack tells the tale of the impressive atmospheric river event from Feb 27-Mar 1.  The previously weak and wet upper snowpack should be gaining strength with every good overnight refreeze.  Several days out from our major storm and avalanche cycle, we expect avalanche concerns to be limited to the recent snow.  You can find vertical drainage columns (percolation channels: see photo) between layers adding strength to the snowpack. 

You won’t have to look far to see the effects of this past week’s storm. Debris piles litter the landscape. While most of these slides were modest, several very large avalanches were reported (see photos below). You can find more avalanches from this cycle on our avalanche observations list. This event also shaped the surface and travel conditions. You may encounter frozen debris, open creeks, bumpy runnels, breakable crusts, and firm slopes as you travel. Give yourself extra time to deal with these potential challenges.

Regioni coperte