Lawinenlagebericht

East Slopes Central

Northwest Avalanche Center
Auf der Karte ansehen

Lawinengefahr

Mon
Hochgebirge
4 · Gross
Waldgrenze
4 · Gross
Unterhalb
4 · Gross
Open full map
Veraltet — dieser Lagebericht ist 6 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

New snow and wind will kick off a round of very large and deadly avalanches. Avalanches could break widely across terrain features, onto adjacent low-angled slopes, and run to low elevations. Avoid traveling in or under avalanche terrain and put an extra-large buffer of terrain between where you travel and slopes steeper than 30 degrees.  

Lawinenprobleme

  • Persistent Slabs

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

    Persistent slab avalanches are very dangerous, surprising, and difficult to predict. They can propagate widely across terrain features and can result in very large and unsurvivable avalanches. Stay out of all avalanche terrain. Make sure to stop and regroup in places that are well away from and out from under avalanche paths. Avoid going near or underneath large slopes, as you could trigger avalanches from far away. We expect that 6 inches to 1 foot of heavy snow with southerly wind will tip the balance of the snowpack and bring natural avalanches by Sunday evening. 

    Stay alert to signs of instability such as recent avalanches, shooting cracks, and whumphing collapses.  Since mid-week, observers have reported triggering avalanches in recent snow and widespread collapsing in the Icicle drainage, mountains near Leavenworth, and the Wenatchee Mountains. Observations show a variety of slopes to be prone to the problem. In the top 2-3 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 steeper than 30 degrees.

    (1/28/2021) A skier intentionally triggered this avalanche (D2) in Icicle Creek on a north aspect at 3800ft that entrained soft snow and ran several hundred feet. The avalanche likely ran on the most recent (1/14) crust and associated weak snow (facets or surface hoar).

  • Loose Wet

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

    Warm, moist snow will fall at low elevation and could result in wet avalanches. In the past couple of days, observers have easily triggered avalanches involving snow that fell since the 24th. For Sunday, similar wet avalanches could become large on steep, sustained slopes and in gullies. While these avalanches may be easier to predict they can still be dangerous and they could trigger a deadly persistent slab. There's a lot of uncertainty in the snowpack and it's best to avoid triggering any avalanches. With that in mind, head the travel advice above.

    (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 natural avalanches, widespread whumphing collapses and cracks shooting through the snow. These have been at all elevations. Layers of concern are in the top 60cm or 2.5 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