Lawinenlagebericht

West Slopes South

Northwest Avalanche Center
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Lawinengefahr

Thu
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
Veraltet — dieser Lagebericht ist 6 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

A relative lull in the weather should allow the avalanche danger to easy slightly Wednesday. However, you may still trigger avalanches near convex rollovers, on very steep slopes, and in wind drifted terrain. Use small inconsequential slopes to help you observe the new snow and how it may fail under your weight.

Lawinenprobleme

  • Storm Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    While none of the recent storms have been large by Cascade standards, the snow continues to pile up above our most recent crust. Changes in snow level, precipitation intensity, wind speed, and breaks between systems created several inter-storm layers that could fail and create avalanches. Take time to identify and avoid the features where you are most likely to trigger an avalanche. Steer around convex rollovers, very steep rocky slopes, and areas where the wind drifted the snow into deeper slabs. You can use small inconsequential slopes to test the snow as you travel. Up-track test, small slope cuts, and simple hand-pits can clue you into potential avalanches. 

    Over the past few days, buried surface hoar and small facets were reported within the upper snowpack. They may exist about 4” (10cm) above a stout crust (12/09). So far we have not seen any avalanches on this layer, but as the slab above them grows, that could change. If you see long shooting cracks or hear whumpfs, dial back your slope angle. Avalanches failing on these weak snow grains can fail in surprising ways and trigger remotely.

    (12/15/2020) Example: This natural storm slab occurred at Lanham Creek near Stevens Pass. It failed on a change in snow crystal type within the storm snow. NE aspect 5200' N-SS-D1-I

Avalanche Discussion

The storms in the West South keep piling on a few inches of snow here and a few inches of snow there. While it’s difficult to measure an exact value, most locations seem to have accumulated between 8 and 15” of recent snow over a very prominent crust (12/09). With every added inch, one has to wonder, when we’ll reach the tipping point and see an avalanche cycle. Tuesday night and Wednesday’s modest water numbers don’t appear to push us over the edge, but time will tell. Due to this incremental loading, a bit of uncertainty exists in the avalanche forecast. 

The new snow may hide many early season obstacles. Warm, wet, and windy weather last week took a toll on the snowpack creating thin cover on southerly slopes and along wind-exposed ridges. Expect open creeks, thin coverage within the forest, and many shallowly buried hazards. 

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.

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