Lawinenlagebericht

East Slopes North

Northwest Avalanche Center
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Lawinengefahr

Sat
Hochgebirge
3 · Erheblich
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Kernpunkte

On Friday, it will be easy to trigger avalanches in wind-drifted snow. Avoid steep, wind-exposed slopes where drifts formed at middle and upper elevations. Stay off steep northerly aspects with the potential to trigger large and surprising avalanches on old weak snow. 

Lawinenprobleme

  • Wind Slabs

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

    Steer around slopes steeper than 35 degrees where the wind has drifted deeper pillows of snow. If you see cracks shooting out from your equipment, stick to lower-angle slopes. Textured snow surfaces and fresh cornices can help identify wind-loaded areas. You can also use small wind-affected test slopes to see how the snow reacts. There is a chance that a smaller wind slab could step down to more deeply buried weak layers, becoming a very large and dangerous avalanche. A very windy storm sculpted the recent snow on the heels of multiple days of incremental storms totalling 1-1.5 feet of snow in the last week. On Thursday, observers reported cracking and triggering avalanches in fresh wind slabs.

    (11/26/2024)

    Shooting cracks in wind-drifted snow. 7,200ft, W. West fork of Cedar ck

    Photo: Will Govus

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    2–3

    The best way to manage this problem is to avoid steep slopes on northerly aspects at mid and upper elevations. Avalanches may be easier to trigger near exposed rocks or wind-loaded slopes. Persistent weak layers take significant time to gain strength. This problem requires careful decision-making and patience. The recent snowfall and significant wind-loading could be making these avalanches more likely, and the consequences remain serious. These avalanches could be unsurvivable, breaking across entire slopes and running long distances.  In two separate involvements in late February near Harts Pass, snowmobilers were buried and one person was killed. More recently, observers in this area found test results showing that the weak layer hasn't gained strength.

    (2/28/2025)

    A large avalanche near Hart's Pass that caught 2 snowmobilers and resulted in one fatality on February 28th. 

    HS-AM-D2.5-R4-O. Cone Mtn, NE, 6,800ft

    Photo: NCH

  • Loose Dry

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

    Keep an eye out for roller balls and other signs of the sun warming the snow surface. As the day progresses, you may be able to trigger slides. Time your travel with the sun and don't linger on slopes with steep, overhead terrain where slides can come down from above.

    (3/5/2025)

    Dry loose avalanches ran over older persistent slab crowns from avalanches at the end of February

    Photo: Drew Lovell

Avalanche Discussion

Friday will bring a bit of a break in the weather, but the danger will remain elevated. 

On Thursday, observers triggered a number of small wind slab avalanches at upper elevations in the Highway 20 corridor. Observers at Harts Pass reported cracking in wind drifted snow. They also found largeand small column tests indicating that propagation is likely on the January Drought Layer. That said, their tests also indicated that you may need to find a shallow area to trigger the weak layer. 

A late February storm brought 18" of snow to the area and was followed by a prolonged warm weather into early March. This resulted in a widespread natural avalanche cycle, first persistent slabs, and then wet loose and wet slab avalanches. Observers reported many large to very large avalanches with widely propagating crowns. The weak layer (January Drought Layer) is buried 2–3.5 ft (70-120cm) below the surface in the Washington Pass and Harts Pass areas. Near Rainy and Easy Passes, the JDL is over 4 feet deep and capped with a thick melt-freeze crust. Aside from getting deeper, the weak layer hasn't changed significantly since the active avalanche cycle. 

NWAC Forecasters visited the site of the avalanche fatality near Harts Pass that occurred on 2/28. You can read the initial observation here. 

 

You can help us gather more data by submitting an observation HERE or via the Avy App. 

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