Lawinenlagebericht

East Slopes Central

Northwest Avalanche Center
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Lawinengefahr

Wed
Hochgebirge
2 · Mässig
Waldgrenze
1 · Gering
Unterhalb
1 · Gering
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Kernpunkte

You could trigger an avalanche in lingering areas where winds formed deep drifts over weak snow. Steep slopes below ridgelines, the base of cliffs, and confined gullies are likely places to encounter this problem. Look for textured, rippled snow surfaces and steer around steep terrain, where you find a thick layer of stiff snow over softer snow. 

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–1.5

    There are lots of variable wind-affected surfaces throughout the zone. In some areas wind slabs formed over a layer of weak, faceted snow and could still be reactive. Unfortunately, differentiating these wind crusts and stiff windboard from pockets of thicker wind slabs can be challenging. Consider finding a low-angle representative wind-affected slope, digging down, and identifying a weak snow structure with a thick layer of stiff wind slab over weaker snow. If you find this stiff layer more than just a few inches thick and it slides easily on the layer below, it is best to stick to lower-angle slopes. You can also use your probe or pole to feel how thick this layer is as you travel. 

    Observers in the Teanaway and Icicle Creek drainage have found these wind slabs over weak snow to be reactive in snowpack tests and isolated test slopes. Although similar slopes seemed more stubborn, yielding no signs of instability. This inconsistency creates uncertainty about where lingering reactive wind slabs exist throughout the terrain. Consider this uncertainty and build larger safety margins into your travel plan with lower-angle options if you find a poor snowpack structure. Shooting cracks, collapsing, or recent avalanche activity are all signs to back off steep slopes. 

    (1/13/2025)

    Stability test results produced unstable results on weak snow below a stiff 1ft thick wind slab on Monday, Jan 13th.

    Photo: Julz Holder - Grounding Truth

Avalanche Discussion

Expect a day similar to Sunday on Monday. With mild temperatures, inversions in the valley, and breezy conditions in alpine terrain. There is a chance that slightly warmer temperatures and more sun will increase wet loose avalanche activity. But with the stiff, wind-affected, and crusty snow surfaces, we expect this to be fairly limited. That said, if you notice a lack of high cloud cover and snow becoming moist and rollerballing, small wet avalanches on steep south-facing terrain are more likely. 

On Monday, an NWAC forecaster reported weakening snow surfaces that produced dry, loose avalanches in steep terrain. This problem could become more widespread with chilly, clear nights. Be aware of your partner, and avoid sluffing them out on steep slopes. 

NWAC Forecasters traveled to Icicle Creek and Salmon La Sac over the weekend to investigate the presence of wind slabs and recent weak interfaces of surface hoar and faceted snow. We both found signs of wind loading at all elevations, but signs of instability didn't appear until above 5000ft. The overlaying slabs were small but wanted to slide on a slick crusts or weak, faceted snow. With clear weather, cold nighttime temperatures, and mild days, we expect the wind slab problem to continue to become less reactive, but with persistent grains involved, we might hold onto this problem longer than we'd like. At lower elevations, crusts and refrozen chunder limit the avalanche hazard, however the challenging travel is a hazard in itself. In sheltered terrain we found isolated surface hoar and more widespread faceted grains on 1/10 interface, while this is a layer to track moving forward, there currently isn't enough cohesive snow over this layer for avalanche concerns. 

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