Lawinenlagebericht

East Slopes South

Northwest Avalanche Center
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Lawinengefahr

Wed
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Kernpunkte

Tuesday will be a cold day in the mountains. An uptick in east winds may build a fresh batch of wind drifted slabs in exposed terrain. The risk of triggering a larger avalanche breaking 1-2 ft deep remains a concerning possibility in areas closer to the Cascade Crest. 

Lawinenprobleme

  • Wind Slabs

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

    An uptick in east winds may stir up our low density new snow and build a new generation of shallow slabs across the landscape. East winds have a tendency to build slabs in unusual areas which can easily surprise backcountry travelers. With that in mind, you’ll want to keep these slabs on radar as you move from aspect to aspect. 

    Visual clues like blowing snow and wind-stiffened surfaces can help you identify where slabs may lurk. Tweaking small test slopes or completing quick hand pits are also a great way to track the sensitivity of the newly forming slabs. Shooting cracks, audible whumphs, and hollow-sounding snow are all signs that you found an unstable slab. 

    While less likely, any triggered wind slab could become a large avalanche on slopes that face NW-NE. Read below for more details.

    (2/14/2024)

    Signs of wind loading, particularly during an east wind event. Use these visual clues to help identify wind-loaded aspects.

    Photo: Andy Harrington

  • Persistent Slabs

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

    Triggering a large avalanche that breaks 1-2’ deep on a layer of facets remains a possibility in the East South, especially during periods like this when we see an uptick in wind speeds and loading. While there haven't been any confirmed avalanches on this weak layer in the East South, we know the structure exists. This avalanche problem will be most problematic in wind loaded terrain or in places like Nelson Ridge, the east side of Chinook Pass or up the South Fork of the Tieiton.

    Unfortunately, this problem is not straightforward to manage. You may or may not get feedback before triggering a surprising avalanche. The best tactic during this time will be to avoid wind loaded terrain that faces NW-NE and steer around steep, open slopes in more sheltered terrain. Shooting cracks, audible whumphs, or unstable snowpack tests are great reasons to dial it back.

    (1/6/2021)Photo: Jake Larson

    An example of a persistent slab from a previous season in the East Central. 

Avalanche Discussion

Be sure to pack the extra layers if you head out on Tuesday. The combination of moderate east winds and temperatures maxing in the teens will make for a very chilly day for mountain travel.

The likelihood of triggering a large avalanche is slowly decreasing, the consequence has not changed. This poor snowpack structure has many time avalanche professionals still traveling conservatively despite the lack of recent signs of instability. It's hard to say if an uptick in wind speeds will be enough to tip the scale for some areas, but it may be wise to travel like it could. Stack the odds by sticking to well-supported terrain and enjoy high-quality powder riding in more sheltered terrain. 

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