Lawinenlagebericht

East Slopes South

Northwest Avalanche Center
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Lawinengefahr

Sun
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
2 · Mässig
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Veraltet — dieser Lagebericht ist 3 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Steer around pockets that appear wind-textured and drifted. These smaller avalanches could grow very large if they step down to old snow 2-4ft below the snow surface. You can reduce your exposure to this problem by sticking to simple terrain less than 30 degrees. 

Lawinenprobleme

  • Wind Slabs

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

    With plenty of soft snow available for transport, look for wind slabs lurking in exposed areas. As east winds pick up, you may notice these slabs forming in unusual places like west aspects or across terrain features (cross-loading). However, you’ll likely still encounter the largest slabs on leeward slopes at middle and upper elevations. 

    Blowing snow and drifting should show exactly what aspects are loading up. As you move through the terrain, pay attention to changes like snow stiffness and texture. You can look for surface clues like sharp cornices, rippled snow, and pillow-like slabs to help you identify problematic slopes. Pull back and default to less steep slopes if you notice obvious signs of instability like shooting cracks or audible whumping. 

    Any triggered wind slab has the potential to step down to old snow and break wider and deeper than expected. Your best bet will be to carefully evaluate and avoid steeper terrain that appears to be wind-affected. See more below. 

    (12/30/2022)

    Use visual clues to help you identify wind-loaded slopes. In this case, cornices often point you in the direction of the wind loading. 

    Photo: Joe Dellaporta

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    2–3

    You can trigger large, unsurvivable avalanches at middle and upper elevation slopes that hold weak snow resting on a crust 2-4 ft below the snow surface. These types of avalanches can propagate widely and pack a punch if triggered. As this active period tapers, you may become less likely to trigger these avalanches - but unfortunately, the consequence stays the same. So consider avoiding slopes greater than 30 degrees, especially in areas with recent wind drifting. 

    On Wednesday, Mission Ridge Ski Patrol triggered multiple avalanches that failed on weak, faceted snow over the Solstice Crust, and a backcountry traveler near Lake Wenatchee remotely triggered a small avalanche on a steep convexity on this same layer. Buried surface hoar (1/2) was responsible for two other human-triggered avalanches before this storm. We have yet to hear about more recent avalanches on this surface hoar layer, but it could still be an issue. With both layers potentially lurking below the surface, extra caution and wide safety margins in your travel plans are warranted. 

    (1/10/2024)

    Backcountry travelers near Lake Wenatchee remotely triggered this avalanche from a low angle adjacent slope. This avalanche ran on weak, facted snow over the Solstice Crust.

    Photo: Pat Riffie

Avalanche Discussion

On Friday, the East South picked up another 8 inches of low-density snow in favored locations. The riding conditions are becoming all time, but be aware of monsters lurking in the basement. Observations from both the West South and East Central have illustrated avalanches breaking in surprising ways and failing on old snow above the solstice crust. The only way to know is to dig down 2-4 ft deep and look for weak snow adjacent to a crust. In some cases, observers have also reported buried surface hoar at similar depths. 

Saturday is shaping up to be a very cold day in the eastern mountains. So be sure to bundle up if you head out!

Let us know what you see by submitting a public observation.

 

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