Lawinenlagebericht

Stevens Pass

Northwest Avalanche Center
Auf der Karte ansehen

Lawinengefahr

Wed
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
3 · Erheblich
Open full map
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Kernpunkte

Light snow will continue with southwest wind. You can trigger avalanches in the recent snow and they could be big enough to bury you, especially at upper elevations. Avoid steep slopes if you see recent avalanches, shooting cracks, or test slopes that slide easily.

Lawinenprobleme

  • Storm Slabs

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

    Consider avoiding terrain 35 degrees and steeper, especially on leeward slopes near and above treeline. It will be easy to trigger avalanches at upper elevations where they could also be larger. Avoid areas where the wind drifts thick pillows of snow or wind features.  Use tests to check how easily the snow slides before committing to steep slopes or larger pieces of terrain. Look for signs of instability such as recent slab avalanches, shooting cracks, and whumphing collapses. The recent storm snow and upper snowpack layering is complex and could result in surprising avalanches. You could trigger avalanches from a distance, from the sides of steeper slopes, or beneath them. 

    Example storm slab from earlier in the season. 

    Photo: Josh Hirshberg

Avalanche Discussion

On Monday, observers reported about 14" of new snow. Avalanche workers with Stevens Pass Resort and WSDOT triggered avalanches at the new/old interface up to size D2. Notable were some very clean and consistent test results below treeline in Henry Creek on the December 29th interface, about 1.5 feet (50cm) below the surface. On Sunday, an observer reported remotely triggering a small avalanche on this interface. Elsewhere, this interface has been less problematic. The new snow is covering up very large surface hoar, sharp faceted surfaces, and very low-density stellars in most places and elevations. On southerly aspects, there are a couple of thin suncrusts with faceted grains between. Check out this ob from Lichtenberg on Friday which documents that layer well. At higher elevations, there are thicker slabs resting on faceted grains underneath the newer snow. Over 3 ft below the surface you can find weak layers on either side of the thin Solstice crust. 

As we head into this next storm cycle, we could begin seeing avalanche activity in unusual places. Slabs have been failing at the new/old interface, but could begin stepping down to deeper layers. A very wide, very large avalanche ran off the E Face of Mt Mastiff around the 26th. Very large avalanches have been occurring in the West North zone on a deeply buried layer of surface hoar. While these very large avalanches may be unlikely, future storms could begin to tip the scales. 

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