Lawinenlagebericht

East Slopes North

Northwest Avalanche Center
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Lawinengefahr

Tue
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
Veraltet — dieser Lagebericht ist 4 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

You could still trigger avalanches in areas where the wind has drifted snow. Look for these pillow-like drifts near ridges, confined terrain features, and at the base of cliffs in exposed areas at upper elevations. Observe how snow reacts before committing to steep slopes, and choose low-angle routes if you observe shooting cracks or mini avalanches on small test slopes.

Lawinenprobleme

  • Wind Slabs

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

    Washington Pass picked up at least 6" of new snow on Saturday, and a few more inches of snow are likely on Monday. Winds have shifted directions and transported snow onto various aspects, forming stiff wind slabs. On northern aspects, slabs may rest over weak snow surfaces and could still be triggered easily. You can observe how the new snow reacts with hand pits, skin track tests, and small test slopes. Look for deeper drifts and shooting cracks as you gain elevation. Steer around these "fat" looking drifts if you see red flags like shooting cracks. Aside from slabs, an NWAC forecaster observed dry loose avalanches that ran surprisingly long distances on Sunday. While these were not large enough to bury a person, use caution in extreme terrain where you could be knocked off your feet and take a consequential fall. 

    (2/4/2023)

    Small fractures on test slopes in wind-affected areas are a great clue to instability.

    Photo: Katie Warren

Avalanche Discussion

Observers noted ski triggering small slabs at upper elevations on Saturday. These were both from upper elevation northeast aspects near Kangaroo. NWAC observer Willie Webster was out in the Pasayten wilderness on Thursday and found a shallower snowpack vs. the Washington Pass area but similar surface conditions, snowpack structures, and generally low avalanche hazard. As we slowly add new snow over old surfaces, we'll have to monitor how older interfaces begin to react to the change. We expect avalanche danger to generally increase as more snow adds up.

Before this pattern change, recent warm temperatures and sunshine on the 25th and 26th formed crusts on steep, sun-exposed slopes. The snow on the surface and directly above the MLK crust began to facet and weaken on shaded slopes. Some observers have reported propagating test results on this layer. We've also been tracking a layer of buried surface hoar from January 5th. Near Washington Pass, it's around 2.5ft below the snow surface but shallowly buried in the easternmost portion of the zone. Snowpack tests indicate the potential for propagation above about 5,500ft or in eastern parts of the zone, where the overlying MLK crust is thin or not present. 

The snowpack near the eastern edge of the zone is more shallow, and you may find weak layers of snow more susceptible to triggering an avalanche. In the lower-elevation foothills, warm and wet conditions transformed previously weak, low-elevation snow into melt forms. While we have little recent info here, we suspect weak layers are forming adjacent to crusts in the upper half of the snowpack.

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