Avalanche forecast

East Slopes Central

Northwest Avalanche Center
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Avalanche danger

Fri
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Highlights

You can trigger large avalanches near and above treeline where the wind built fresh slabs of snow earlier this week. Use caution on slopes over 35 degrees, especially where the wind has drifted recent snow into deeper slabs. Give the snowpack some time to adjust to the recent snow before traveling in steep, consequential terrain.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2

    Use caution in avalanche terrain where the wind has drifted snow. The most likely places for wind slabs to develop are near ridgelines, convex rolls, and the base of cliffs, especially above treeline.  Use visual clues, like textured surfaces and "fat" looking drifts, to identify stiff wind slab locations. Stick to forested areas, sheltered from recent winds.

    By Wednesday morning the central portion of the region including the Highway 2 corridor, mountains near Leavenworth, and the Wenatchee Mountians received up to 8" of snow overnight. South and western portions of the zone were favored in previous days with over a foot of new snow with ridgeline winds over 30mph. Recent slabs formed over various slick or weak snow surfaces. You can used snow profiles to look for any weak layers that may have been buried at the beginning of the storm.

    (1/29/2023)

    Like in this example, actively blowing snow is a sure sign of wind slabs on the slope below. 

    Photo: Dallas Glass

Avalanche Discussion

Near the Cascade Crest, you can find 1-2 feet of recent snow that accumulated since February 3rd. Strong wind during the storm, followed by sun on Wednesday affected the surface snow. On Wednesday, observer reported loose wet avalanches on steep sunny slopes of rock Mountain near the western border of the zone.

Earlier this week, Katie Warren went to the westernmost and easternmost edges of the East Central zone. Not surprisingly, snowpack conditions in these locations are quite different. A deeper and stronger snowpack exists in the western portion of the zone, and further east, a shallower snowpack with more prominent and concerning buried weak layers. Common landmarks in these snowpacks are the MLK crust and the Christmas Crust, buried .5-1.5ft deep and 3-4ft, respectively. The recent cold weather weakened the snow above and below the MLK crust into weak, faceted grains, creating a weak structure that we'll watch closely after this storm.

In the lower Little Wenatchee River Drainage, Katie found 300cm of snow at 5600ft that increased in strength with depth. Just outside of the Mission Ridge Ski area on Sunday, the height of snow was 230cm of snow, and while much of the snowpack was strong 1F or P rounded grains, two prominent layers of buried surface hoar exist. The lower layer of surface hoar, buried on January 4th, is still producing propagating test results, despite being below the MLK crust. We are still tracking this layer but don't anticipate avalanche activity on this layer during this storm. However, a layer of surface hoar, buried on January 18th, may produce avalanches with this new snow load. So keep it in your mind, and choose conservative terrain, if traveling in the Wenatchee Mountains. 

Regions covered