Bollettino valanghe

East Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

Mon
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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In sintesi

Another sunny, warm day will renew wet avalanche concerns on steep, sunny slopes. Default to shadier terrain once you notice rollerballs shedding or sticky wet snow under your feet or machine. At upper elevations, use caution around wind-drifted slopes and assess for instability before committing to bigger terrain. 

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    The sun and warm temperatures will renew the wet avalanche problem once the surface crust breaks down. You'll initially see signs of warming and wet avalanches beneath rock bands or on steep slopes with direct sun exposure. As the day progresses, you may notice signs of warming on east and west aspects as well.

    Rollerballs, pinwheels, or sticky, sloppy snow surfaces usually indicate that surfaces are becoming wet and weak. Look for more shaded aspects once you start noticing these signs. 

    If you see slides breaking into slabs, gouging deeper, or growing larger, the scales have tipped, and you’re dealing with a much more dangerous wet avalanche beast. Put space between you and these slopes.

    (3/7/2024)

    Rollerballs and pinwheels are obvious precursors to Wet Loose avalanches.

    Photo: Kaitlin Harrigan

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    If you climb to upper elevations, you may still find some lingering stubborn wind slabs. An uptick in north winds may build a new generation of slabs, but these will be shallow, but still worth keeping on your radar in steeper, consequential terrain. 

    Managing this problem is fairly straightforward. Be suspicious of any terrain features that promote drifting. You can typically find these on the downwind side of ridges, below cornices, and beneath rock and cliff bands. Using small test slopes or doing quick hand pits is a great way to gauge the reactivity of these slabs. If you notice blowing snow, textured rippled surfaces, hollow drum-like snow, or shooting cracks under your sled or feet, default to more sheltered lines. 

    (12/31/2023)

    Steer around wind-loaded features if you notice signs like this. 

    Photo: Joe Dellaporta

Avalanche Discussion

Preliminary Report: NWAC is saddened to report an avalanche fatality as a result of a cornice fall on Mount St Helens. On Saturday, March 30, 2024, a snowboarder summited the peak. While standing near the top, he triggered a cornice and fell to his death. Our deepest condolences to the family, friends, and community.

Discussion:

On both Friday and Saturday, backcountry skiers triggered small D1 avalanches in the Mission Peak area. These avalanches broke 9-12 inches and occurred on east aspects at approximately 5800 ft. You can check out their observations here and here. Around the same area on Friday, an NWAC forecaster found a layer of buried surface hoar within the recent snow. We're still figuring out how widespread surface hoar is - but it's worth noting if you travel in the Blewett Pass and Mission Ridge backcountry. 

Even though we aren't forecasting persistent slabs, the weak layer is still there. It's been a few weeks since we've seen an avalanche on the facets over the Early February Crust. While not impossible, it is very unlikely you'd see an avalanche on this deeper layer. It would likely take a bigger trigger in higher elevation shaded terrain to result in a slide. If you're traveling in these areas, factor that into your uncertainty when discussing terrain. 

At lower elevations, the snowpack is thin and even sometimes discontinuous. Even though these snow down low is wet and weak, this helps all but eliminate the avalanche risk.

If you get out this weekend, let us know what you see by submitting a public observation here. 

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