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

Wet and dry snow avalanches will be a concern anywhere you find 6" or more above a firm crust. With more sunshine in the forecast, steer away from slopes warming in the sunshine. Small drifts up to a foot deep lurk for human trigger on upper-elevation lee slopes, particularly near ridgelines.

Problemi valanghivi

  • Loose Wet

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

    We're expecting more sunshine on Sunday than on Saturday. Any extended appearance of the sun will result in small wet loose avalanches on directly exposed slopes. The longer a slope exceeds, 35 degrees, the more momentum a wet loose avalanche could gain. Adjust your aspect to seek cooler slopes if rollerballs start appearing on slopes with 4" or more of snow.  These avalanches start with snow dripping off rocks, cliffs, or trees, or a human triggering a small avalanche that gains steam as it entrains dry snow atop the crust. Consider the slopes above you and your exposure to terrain traps such as cliffs, rocks, or creeks as you plan your tour.

    (4/5/2024)

    A small "push-o-lanche" (wet loose) slide. Even though this avalanche was tiny, it would be a nasty ride if it pushed you into the open creek below. 

    Photo: Dallas Glass

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    1

    You can trigger a small slab in isolated areas, such as lee slopes and shaded terrain features near ridgelines at upper elevation slopes. Fresh slabs will form in areas with active or recent wind transport. Actively blowing snow and textured snow surfaces should tip you off that wind slabs lurk in your terrain Look for sharp cornices, and evidence of snow movement around rocks. In western and northern portions of the zone, it won't take much wind to drift a 6-12" slab that you can trigger and you'll need to be more alert to the problem. Further east, winds are more likely to scour many slopes to a crust, so it should be to identify lens-shaped drifts in the immediate lee of ridgelines.

    Simple hand shears or slope tests on inconsequential wind-loaded terrain features can help you assess the bond to the crust and the cohesion of the slab. These slabs can be triggered on slopes 35 degrees and steeper and will be most consequential in extreme terrain or above terrain traps.

    (2/23/2024)

    Look for textured wind-affected snow surfaces where you might find a wind slab nearby.

    Photo: Dallas Glass

Avalanche Discussion

We're expecting up to two inches of additional snowfall through Sunday, with the most in convergence spillover. Several rounds of snow have brought 2-6" above the last major crust and we're expecting this snow depth to remain similar through Sunday as the older snow settles. The crust burial date ranges from 4/4 in the east to early on 4/3 in the west. Avalanche entrainment is expected to be limited to the snow above this crust. 

On Thursday, Katie Warren was in the Wenatchee Mountains and found a few inches of new snow over a supportable crust. Moderate winds were drifting the snow around, but this didn't result in any notable wind slab formation at mid-elevations. They found isolated pockets of shallow wind slabs at the upper elevations. 

Recent reports noted less snow at lower elevations than is typical for early April, so be prepared for some interesting and challenging travel conditions. Katie experienced slippery, icy trail conditions below 5000ft on Thursday in the Wenatchee Mountains. It might be worth packing traction devices for summer trail approaches to reach a more consistent snowpack at higher elevations or if you travel in wind-scoured areas.

Let us know what you see as you travel in the mountains by submitting a public observation here. 

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