Avalanche forecast

East Slopes Central

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

7a update: More overnight snow than forecast in the Highway 2 corridor. Overnight wind and snow will make it easy to trigger large avalanches near and above treeline. Use extra caution on slopes over 35 degrees, especially where the wind has drifted recent snow into deeper slabs. If the new snow slides easily in snowpack tests or recent avalanches at any elevation, stick to lower-angle slopes.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Look for signs such as rollerballs and pinwheels to indicate these wet avalanches are possible. If you see this, move to more shaded, lower-angled slopes. Warming temperatures and sun could initiate point releases on steep sun-exposed slopes, especially midday and afternoon. Use caution near terrain traps. Loose wet avalanches can be dangerous if they push you off of rocks or into trees or gullies. 

    (1/25/2023)An example of small wet loose avalanches triggered with ski cuts, or stomping and breaking off small cornices. Photo: Katie Warren

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–2

    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. Look for actively blowing snow and use visual clues, like textured surfaces and "fat" looking drifts, to identify stiff wind slab locations. Stick to forested areas, sheltered from these strong 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. You should anticipate sensitive wind slabs developing in any terrain not sheltered by thick forest. These slabs will form over various slick or weak snow surfaces and may run farther than you anticipate. 

    (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

A series of smaller storms brought refreshes of snow, but this storm will be the first major event since the MLK storm for the eastern slopes of the Cascades. The new snow buried a complex array of surfaces, from stiff wind-board and slick crusts to weak faceted snow on high-elevation north aspects. This setup means snowpack conditions may become tricky after this storm exits the area. The snowpack will need time to adjust to this new load. 

Over the last few days, 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