Lawinenlagebericht

East Slopes North

Northwest Avalanche Center
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Lawinengefahr

Thu
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist 6 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

You can trigger a large slab avalanche on steep slopes at upper elevations where thick, cohesive slabs may have formed. Look for signs of instability. Identify and avoid slopes and features of concern as you travel.

Lawinenprobleme

  • Wind Slabs

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

    It will be possible to trigger a large slab avalanche on Wednesday due to new snow and strong wind. Keep an eye out for signs of instability such as shooting cracks or collapsing of large sections of snow with a person's weight. Look for dense, cohesive slab buildup as you gain elevation. Wind slabs may feel punchy as you travel over them. Other clues that indicate wind has drifted the snow are the presence of drifts and cornices. Even if there isn't much new snow, the winds at upper elevations may have created cohesive slabs with existing snow. These could be hard to discern or buried under a few inches of fresh. You are most likely to trigger an avalanche on northwest through southeast aspects in the alpine, and on slopes 35 degrees and steeper. 

    Remember, it is still early season and the snowpack is shallow. Consider the consequences of even a small slide, which could result in a rough ride. Obstacles like hidden stumps, rocks, and open water still abound. 

    Example wind slab fracture.

Avalanche Discussion

The forecast comes with a fair amount of uncertainty about previous snow structure. What we do know is that the snowpack near Washington Pass is generally 3.5ft to 5ft deep. Over the weekend, observers found good coverage and travel conditions. Observers identified a snowpack with a favorable hardness structure and stability was generally good. However, one isolated large avalanche was noted (see photo in media gallery). This slide occurred on a North aspect at about 7,000ft in Liberty Bowl. The crown was over 3ft deep, and it appeared to have run on weak snow above a melt freeze crust near the ground. Our best guesses date it back to 11/18 or so. Although no other snowpack observations found weak snow near the ground, this is direct evidence that it is out there and could be a problem in very isolated locations in the future. 

Check out our new observations platform, and consider submitting an ob if you get out. Now is a great time to run through your safety equipment, and check to make sure everything is in good working order. Check my recent blog post on it here!

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

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