Lawinenlagebericht

East Slopes North

Northwest Avalanche Center
Auf der Karte ansehen

Lawinengefahr

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

Kernpunkte

You could trigger very large avalanches on deeply buried weak layers, especially at middle and upper elevations. Seek out lower-angle, supported terrain while this dangerous problem lingers. You may be able to trigger small avalanches due to fresh drifting from southeasterly winds at upper elevations.

Lawinenprobleme

  • Persistent Slabs

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

    Put a larger buffer of terrain between your group and large start zones or complex avalanche paths above 6,500ft. Choose smaller, supported slopes and stay well out from under larger features. Signs of instability can be inconsistent, creating a tricky problem that is essentially 'unmanageable.' You might not receive signs of instability before the whole slope fails. Facets that were buried throughout February can be found over a crust in the top 2-4 feet of the snowpack. There's copious evidence of these layers being the culprits of numerous very large natural avalanches and close calls in the zone. 

    (3/5/2024)

    A very large avalanche was remotely triggered by skiers on 3/2 on Kangaroo Ridge. The crown was ~70-100cm deep, and it ran on a layer of facets (1.0mm) buried in mid-February, just above the 1/31 crust.

    Kangaroo Ridge, Pk 8183, WNW, 7,600ft

    Photo: John Stimberis

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–1.5

    Southeast winds will increase on Saturday afternoon. Though shallow, these slabs could be fairly reactive as they'll have formed over faceted surfaces. Look for signs of wind slabs, such as blowing snow or textured surfaces. You may encounter shooting cracks. While you can easily steer around these small, fresh drifts, you'll need to avoid triggering the much more dangerous, deep persistent slab avalanches. You can trigger these two types of avalanches in similar terrain.

    (1/23/2024)

    An example of plumes of blowing snow over a ridge of Hinkhouse Peak in January. Photo: Josh Hirshberg

Avalanche Discussion

NWAC is devastated to report the death of one of our Avalanche Forecasters, Matt Primomo. Tragically, Matt passed away in a non-avalanche accident away from work on Thursday, March 7th. Matt has been a key member of the NWAC family since 2017. His life in the mountains touched so many people. We are absolutely heartbroken. Please join us as we mourn this immense loss with Matt’s family, friends, and community.

 

Discussion:

Southeast winds may increase enough to transport snow at upper elevations. The strengthening March sun formed crusts on steep SE-SW aspects. Observers reported loose avalanches (wet and dry) on steep, sun-exposed slopes this week. On Tuesday, skiers at upper elevation slopes triggered a few small wind slab avalanches.

On Tuesday, forecasters visited the site of a remotely triggered (D3) avalanche on Kangaroo Ridge. They found that the avalanche was ~2.5-3 feet deep and ran on a layer of facets buried in mid-February, just above the Jan 31st crust. Tests still produced sudden or propagating results indicating that backcountry travelers could trigger similar avalanches, especially in areas of relatively shallow snowpack. There have been multiple reports of close calls, natural avalanches, and snowpack observations in the Highway 20 corridor that point to the deep, persistent slab problem. Widespread, very large natural avalanches occurred between February 28th and March 3rd. In the past week, natural avalanche activity has stopped, and snowpack tests have become more variable, with some showing relatively stable results. In the East Central and Stevens Pass zones, there have been multiple triggered avalanches and involvements this week on a similar snowpack structure.

Snowpack information is limited outside of the Highway 20 corridor and Harts Pass. Let us know what you find if you get out into the backcountry!

Abgedeckte Regionen