Lawinenlagebericht

East Slopes North

Northwest Avalanche Center
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Lawinengefahr

Wed
Hochgebirge
2 · Mässig
Waldgrenze
3 · Erheblich
Unterhalb
3 · Erheblich
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Kernpunkte

Incremental snowfall and warming temperatures may increase the chances of large, persistent slab avalanches on Tuesday. Warming temperatures may also lead to many wet loose and wet slab avalanches at mid and lower elevations. Pay attention to surface condition, and steer away from large, steep slopes while the snowpack undergoes a transition.

Lawinenprobleme

  • Wet Slabs

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

    Rain on snow may lead to wet loose and potentially wet slab avalanches at lower elevations. Wet loose slides have the potential to trigger larger wet slabs that fail 1-3ft deep on old snow and crust layers. Both of these slides can entrain a significant amount of heavy snow and could pack a punch.  Wet slides often start from trees or rocks shedding snow onto slopes below, but you can also trigger them with your skis or snowmobile. If it's raining on dry snow or the snow is very wet and heavy, stick to lower angle slopes and stay out from underneath very large steep features. 

    Roller balls were seen on Jan 21st in low elevation terrain and mid to upper elevation terrain in direct sun

    Photo: Willie Webster

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    2–2.5

    A problematic snowpack structure exists due to a series of crusts and weak layers buried in December, now in the lower third of the snowpack. Observations of large rumbling collapses and unstable snowpack test results have continued to come in over the past week, including the fairly fresh looking large slide that seems to have been triggered by a cornice on the 21st. If you managed to trigger one of these avalanches, it could break 2-3ft deep, and widely across terrain features. Warming temperatures may increase the chances of triggering these on Tuesday.

    Persistent slabs are a tricky problem, often leading to a false sense of security with no apparent signs of instability, such as collapses or shooting cracks. An unlucky individual could hit the wrong spot on a steep slope, and the whole slope may fracture and slide. Maybe it's not the first skier or rider on the slope, but it could be the second or third. Your best strategy is patience and conservative travel choices. Choose well supported and lower angle terrain. Stop and regroup in safer areas, well away from potential runout zones.

    (1/21/2024) Photo: Luke Huntington

    Large, fresh persistent slab triggered by a cornice fall in Cutthroat drainage.

Avalanche Discussion

Temperatures are on an upward trend as we come out of the icebox. Observers reported the impacts of warming temperatures in the past few days. The most notable observation we've received recently was a large cornice triggered slab in Cutthroat drainage on the 21st. Warming temperatures may have had an influence on the cornice failing, and we could see similar and increased activity on Tuesday. On Saturday and Sunday, observers reported rollerballs and small, wet loose avalanches. Observers have been reporting collapses in the Cutthroat Lake area, Varden Creek area over the past week. Deeper crowns have also been spotted, albeit with poor visibility. 

An NWAC observer in the Twisp River area found that the mid-December crust produced unstable propagation saw test results. They also experienced loud whumphs that shook trees as the collapse propagated widely across the terrain. NWAC observers near Mt Tiffany near Conconully found a very thin snowpack, and the deepst area was only 2.5ft deep at 6,800ft. Many slopes have logs and brush sticking through the snow on the ground.

If you're in the mountains, please let us know what you find.

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