Lawinenlagebericht

East Slopes Central

Northwest Avalanche Center
Auf der Karte ansehen

Lawinengefahr

Sun
Hochgebirge
3 · Erheblich
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
Open full map
Veraltet — dieser Lagebericht ist 6 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

You could trigger large and life-threatening avalanches on a variety of slopes. Watch and for cracking, collapsing, and recent avalanches as signs that you should stick to slopes under 35 degrees and avoid large avalanche paths. The best way to deal with this dangerous and complex snowpack is to stick to less consequential terrain.

Lawinenprobleme

  • Persistent Slabs

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

    Persistent slab avalanches are very dangerous and difficult to predict. You may be able to trigger surprising avalanches that propagate widely across terrain features. Use low angle slopes for travel and stick to the high ground like ridges. Avoid going underneath larger slopes, as you could trigger avalanches from a distance. Be especially careful on leeward slopes and terrain features that may be recently wind-loaded.

    Stay alert to signs of instability in the new snow such as shooting cracks, or whumphing collapses. In the top 2 feet of the snowpack, there are a number of weak layers that could all result in an avalanche. These including surface hoar and facets resting on a crust, beneath snow that has fallen since the 24th, as well as more deeply buried facets sandwiched between weak crusts. While the snowpack is complex, the solution is simple. Avoid avalanche paths and features that are big enough to produce large avalanches and put plenty of space between where you travel and slopes 35 degrees and steeper.

    Example persistent slab in the near treeline zone.

  • Loose Dry

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

    In the past couple of days, observers have easily triggered loose avalanches involving snow that fell since the 24th. Avalanches could become large on steep, sustained slopes and in gullies. These avalanches occur where the recently fallen snow is soft and uncohesive. In many cases, they're running on the same weak layers as the persistent slabs. While these avalanches may be easier to predict they can still be dangerous. There's a lot of uncertainty in the snowpack and it's difficult to be sure that you will only trigger loose avalanches and not persistent slabs. With that in mind, head the travel advice above and avoid triggering any slides.

    (1/29/2021) A large skier triggered loose avalanche on N, 3800ft in Mountaineers creek on Jan 29th. Photo: Nate Hough-Snee

Avalanche Discussion

Observers in the Icicle drainage and the Wenatchee Mountains have reported widespread whumphing collapses and cracks shooting through the snow. While these have been at all elevations, they seem most pronounced above about 5,000ft. Layers of concern are in the top 50cm or 2 feet of the snowpack. One of the most problematic weak layers involves a thick layer of faceted grains sandwiched between two crusts about 1.5 feet below the surface. This has been identified in the Icicle drainage, Blewett Pass,  as well as in the upper Chiwawa drainage before the storm. Prior to the snowfall observers also noted both near-surface facets and surface hoar. In sheltered areas, you may find fourteen to sixteen inches of storm snow since the 24th. At upper elevations, you may find slightly stiffer and much thicker slabs. As more snow accumulates, the slab over these weak layers will build and we may see avalanches become more reactive.   

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.

Abgedeckte Regionen