Lawinenlagebericht

West Slopes South

Northwest Avalanche Center
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Lawinengefahr

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

Old wind slabs, ongoing wind transport, and sunny skies will make avalanches possible on Tuesday. Watch for signs of wind-loading, such as blowing snow, textured surfaces, chalky pillows, or dunes, and steer clear of steep, sustained slopes over 35 degrees if you observe these signs. Manage potential wet avalanches by moving to shaded slopes if you notice rollerballs, pinwheels, or moist snow surfaces.

Lawinenprobleme

  • Wind Slabs

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

    Signs of wind slab instabilities are beginning to wain in the West South. As this happens, the problem may migrate into steeper and more complex terrain. The odds of triggering an avalanche will increase with slope angle, where the slab is thicker, and the slope is less supported. Convexities, tops of chutes, aprons at the base of cliffs, and slopes below steep ridgelines are all likely locations to find this problem. You will probably see lots of signs of wind transport, but determining which slope is reactive will be trickier. You can use hand pits and small test slopes to gauge for reactivity, but you need to be sure that the test slope is representative of the start zone on the slope you are considering. Subtle differences in slope angle, aspect, and wind-deposition patterns can make a huge difference in slab presence and reactivity. Carefully assess the slope in question and if you decide to travel on it, only expose one person at a time and keep eyes on your partner. Choose well-supported and planar slopes without signs of wind-loading to put the odds in your favor. 

    (12/15/2024)

    A heavily wind-loaded northerly slope. You can tell how "fat" it is by the textured surfaces and pillow-like drifts.  Be cautious of steep and wind-loaded slopes below steep ridge lines like this one.

    Photo: Andy Harrington

  • Loose Wet

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

    High clouds prevented the southern half of the compass from seeing significant warming on Monday, leaving many slopes still waiting for their first good shot of sun and warmth since the storm. If the sun comes out and stays out on Tuesday, the chance for wet loose avalanches will increase on slopes facing the sun. This problem gives some clear advanced warning signs. Look for rollerballs, pinwheels, snow shedding from trees, and a moist or wet snow surface. If you see any of these, stay off of and out from under steep slopes in the sun. You can shift your aspect to a shadier slope to mitigate this hazard.

    (1/12/2025)

    Avalanche activity on a steep sun-exposed slope on Sunday. High clouds kept these at bay on Monday, but they could make an appearance on Tuesday if the sun comes out in full force. Photo: CVT Crag Rats

Avalanche Discussion

On Monday, NWAC forecasters visited the Tatoosh via the road to Paradise. While they found lots of signs of wind transport, evidence of instability was a bit harder to find. They reported a generally well-settled upper snowpack, with only a few inches of ski penetration. High clouds kept the wet loose problem largely at bay. The upper snowpack changed a bit with aspect, but generally speaking, the 1/10 interface continues to be the lingering question mark. 

We are encouraged by the general lack of reported activity on the 1/10 and the lack of propagation in large column tests. Still, a thick slab over this slick crust on a steep and unsupported feature could produce an avalanche on Tuesday. Soft snow available for transport means that slab depths could further increase and the bond could be tested a bit more. Keep wind slabs on your radar. If you’re after steep terrain, choose non-wind loaded and supported slopes with clean runouts to stack the deck in your favor.  

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