Lawinenlagebericht

East Slopes North

Northwest Avalanche Center
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Lawinengefahr

Fri
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist last year abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Substantial sunshine and warming temperatures will be a big switch for the generally cold and dry upper snowpack. Expect avalanches to become easier to trigger when you see new rollerballs or find wet, sticky snow. As temperatures rise, snow may shed naturally from steep rocky faces basking in the sun.

Lawinenprobleme

  • Loose Wet

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

    In many parts of the zone, cold dry snow sits over a firm crust from the March atmospheric river (AR). This is the snow we’re worried about as sunshine and warm temperatures work to change the surface. At this point in the year, you could see signs of warming on all but the highest and shadiest slopes. Sun breaks over the past few days may have started to change the snow on more southerly slopes. Don’t be surprised if the more off-aspects (NE-E, W-NW) produce the most activity. 

    Expect natural rollerballs as blobs of snow fall from trees and rocks. This will be the first sign that the snow surface is turning. Wet loose slides often follow. Some avalanches may slide easily and travel far over the underlying firm crust. Even if they’re fairly small, they could be impactful. Wet loose slides are often easy to manage, but on longer slopes, these slides could become large and even deadly. Steer clear of steep slopes with wet heavy snow, especially in higher consequence terrain.

     

     

    Loose avalanches triggered by snow falling off rocks. Photo: Adam Butterfield

  • Persistent Slabs

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

    This problem is still on our minds for the eastern portion of the zone and other areas with shallow snowpacks where a stout crust didn’t form following the last AR. As temperatures warm, water may impact these old weak layers and/or change the slab, making avalanches more likely. 

    If you don’t find a firm crust beneath the softer surface snow, assume this tricky problem could be an issue. You’ll likely want to dig and investigate the snowpack before stepping into larger terrain. If you see weak sugary facets or have tests that fail suddenly, steer away from steep open slopes.

    (3/17/2025)

    A widely propagating avalanche near Tiffany Mtn.

    Photo: Willie Webster

Avalanche Discussion

The mountains may look wintery, but Thursday’s weather should make it feel more like spring. Each year, these transition periods are full of surprises. After a generally cloudy and showery week, skies should clear and temperatures rise. On Thursday, we’re primarily worried about the surface snow. However, large looming cornices and blocks of snow clinging to rocks could start to shed with little or no warning. As this warm, sunny weather persists, these avalanches may become more common. Pay attention to what’s above you, and don’t linger under these overhead hazards. 

In the WaPass area Wednesday, DOT and NWAC forecasters found about a foot of cold snow over the AR crust on shaded slopes. At upper elevations, they could see wind texturing and scouring. If you head to the tops of these higher peaks, keep an eye out for lingering pillow-like wind slabs. 

At lower elevations, spring has already started. There’s just not as much dry snow to create a hazard. Expect thinning snowpack and opening creeks.

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