Bollettino valanghe

Snoqualmie Pass

Northwest Avalanche Center
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Pericolo valanghe

Sun
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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In sintesi

With plenty of sunshine on tap for Saturday, any steep southerly slope that hasn’t slid should be suspect. You may see new rollerballs and a few natural loose wet avalanches. Don’t let one of these small slides push you over a cliff or into a creek.

Problemi valanghivi

  • Loose Wet

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

    At mid and upper elevations 4-6 inches of soft snow sits on the surface and the mountains around Snoqualmie Pass have yet to see a full day of sunshine. That means steep sunny slopes that still hold soft dry snow could produce avalanches Saturday. You may see piles of new rollerballs and natural loose wet slides as the sun weakens the surface. This will be most likely on rocky slopes, where the sun can easily heat the ground. While these slides should stay small, don’t let one of them catch you off guard. Even little avalanches can hurt you if they push you into a terrain trap like over a cliff or into a creek. Since this recent snow sits on a thin crust, some of these slides may run farther downhill. Pay attention to the terrain above you and don’t linger under steep slopes basking in the sun. 

    We think the loose wet avalanche activity will stay within the storm snow from March 2-3. However, below the surface crust weak snow may still exist. It would be very difficult to get this older snow into motion, but if you see avalanches entraining deeper layers, the problem has changed. Resulting avalanches would be large and scary. 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 Saturday. 

    Photo: Robert Hahn

Avalanche Discussion

A few more clouds hung around Snoqualmie Pass than expected on Friday. While rollerballs and a few natural loose wet avalanches were reported, much of the snow escaped the sun’s influence. Above 4500 ft, 4-6 inches of dry snow from March 2-3 sits above a thin and often breakable crust. Below the surface, the upper snowpack tells the tale of the impressive atmospheric river event from Feb 27-Mar 1. So far this snow has remained rather weak and unconsolidated below a thin melt freeze crust. That may change Friday night as clear skies and cool temperatures help the older wet snow start to freeze. This will take time, and one night may not be enough. Expect to find firm crusts, layers of weak wet large grains, and pockets of dry small rounds in the upper snowpack. While individual tests may produce failures, we don’t expect these weaknesses to be consistent across a slope and they are unlikely to produce avalanches. Additionally vertical drainage columns (percolation channels: see photo) can be found 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 from Chair Peak (see new photo below), Cave Ridge, Red Mt, and the W Face of Kendall. 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.

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