Bollettino valanghe

East Slopes South

Northwest Avalanche Center
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Pericolo valanghe

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

Triggering avalanches in wind-drifted snow is possible on Friday. Look for stiff textured surfaces, blowing snow, or deep pillow-like drifts to help you pinpoint unstable slabs. Daytime warming and possible sun breaks may moisten and weaken snow surfaces, so consider moving to shadier slopes once you notice gloppy, sticky snow or rollerballs shedding. 

Problemi valanghivi

  • Wind Slabs

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

    Recent new snow and strong winds have built wind slabs on leeward features across the zone. Expect these slabs to be thicker and more widespread as you gain elevation. You'll find more snow and larger avalanches further west, towards the Cascade Crest, particularly in the HWY 410 corridor close to Chinook Pass.

    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. 

    (3/28/2024)

    Mission Ridge Ski Patrol was able to easily trigger these wind slabs with ski cuts on Thursday 3/28.

    Photo: Mission Ridge Ski Patrol

  • Loose Wet

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

    Freezing levels will slowly start notching up in the coming days, increasing the likelihood of wet avalanches. You'll typically notice these wet loose avalanches during sun breaks or daytime warming. Most snow surfaces above 5000 ft are dry and cold, so it won't take much of either sun or warming for the snow to react. Rollerballs, pinwheels, or trees shedding snow are good indications that surfaces are becoming wet and weak. Look for more shaded aspects once you start noticing these signs. 

    (3/5/2024)

    You could see small wet loose avalanches like this on Friday. 

    Photo: Josh Hirshberg

Avalanche Discussion

Trickles of new snow have freshened up surfaces around the East South zone. Areas closer to the Cascade crest, like Bumping Lake and West, have received the most new snow. You'll typically find 1-1.5 ft of recent snow resting over the stout crust left from last week's warm-up. Fortunately, this stout crust helped reduce the likelihood of triggering deeper layers of concern. However, you'll want to shift your focus to surface instabilities such as wind slabs or wet avalanches in the coming days. 

On Wednesday, an NWAC forecaster in the Ahtanum area found around 6" of new snow above 6000ft. New snow depths at lower elevations were significantly less, with rain down at the Snopark. A profile at approximately 6600ft on a NE aspect showed a stout crust below the recent snow. Shovel tilt tests produced moderate results with clean shears on this crust. In sheltered areas, there isn't much of a slab over this crust, but it could make wind slab avalanches easier to trigger. They also found the facets over the Early February Crust to be moist and rounded. This persistent weak layer is getting stronger and, combined with the stout surface crust, makes avalanches on this layer unlikely. However, there is always lingering uncertainty with these tricky, persistent weak layers, so step into large, north-facing alpine terrain with this in mind. A big warm-up or powerful storm could also bring this problem back to life. 

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

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