Avalanche forecast

East Slopes Central

Northwest Avalanche Center
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Avalanche danger

Tue
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Out of date — this forecast expired 3 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

It's going to be a wet, warm day out tomorrow. You could trigger avalanches in wet snow, new snow, or old snow. Most concerning is the eastern portion of the zone, where you are likely to trigger large avalanches that break across terrain features. Make conservative terrain choices and avoid being on or under large open slopes, particularly in the Wenatchee Mountains.

Avalanche problems

  • Storm Slabs

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

    Near the western edge of the zone, 5-8 inches of new snow may build small storm slabs where you could trigger an avalanche. Winds slabs may also form near ridgelines and could be larger and easier to trigger. Terrain over 35 degrees, lee slopes below corniced ridgelines, or steep rollovers are likely areas to trigger an avalanche. Use Kickturn tests, small test slopes, or hand pits to observe the bond to the old snow surface. If these produce cracking or fail easily, avalanches are more likely. 

    Most of these avalanches would be small, but even small avalanches could step down to more deeply buried weak layers, propagate across terrain features, and become very large.

    (1/19/2024)

    Kickturn tests as you travel are a good way to observe the strength of the new/old snow interface. 

    Photo: Caya Johnson

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2–3

    Multiple large, human triggered avalanches ran on the Solstice Crust at Blewett Pass on Saturday. The snowpack in the Wenatchee Mountains is thin and weak. Avoid avalanche terrain if you are traveling in the eastern portion of our zone, near Mission Ridge, Blewett Pass, or the Entiat areas. You could trigger one of these avalanches from low-angle terrain below or adjacent to steep slopes.Persistent slabs are a tricky problem, often leading to a false sense of security with no apparent signs of instability, such as collapses or shooting cracks. But then, an unlucky individual hits the wrong spot on a steep slope, and the whole slope fractures and slides. It may not even be the first skier or rider on the slope. Your best strategy is prolonged patience and conservative travel techniques. Give yourself wide safety margins around large open terrain and avoid steep slopes where a smaller avalanche could step down to these deeper weak layers.

    While we think these avalanches are becoming more difficult to trigger in other areas of the zone, the weak structure still exists but is more deeply buried. If you got unlucky, you could still trigger an avalanche 2-4ft deep that may propagate widely.

    (1/20/2024)

    This avalanche that failed on the Solstice Crust was triggered by a skier on Saturday on Diamon Head, Blewett Pass. Notice the older crown to the left in the photo.

    Photo: Brett Hlavka

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Warming temperatures and rain on the recent snow could produce small wet loose or wet slab avalanches in steep terrain. Wet avalanches often start from trees or rocks shedding snow onto slopes below, but you can also trigger them with your skis or snowmobile. With a few crusts and weaker interfaces in the upper snowpack, wet slabs may also be possible. If it's raining on dry snow or snow becomes wet and heavy, consider moving to lower angle slopes. There is potential for these small wet avalanches to step down to deeper weak layers, triggering a larger slab avalanche 2-4ft deep. Consider these consequences before riding on steep terrain with wet, heavy snow.

    (1/4/2024)

    Rollerballs are one of the first signs that wet loose or wet slab avalanches are possible. 

    Photo: Katie Warren

Avalanche Discussion

Expect highly variable weather and snowpack conditions across the zone. On the western edge, 5-8 inches of snow with rain at lower elevations is likely. Further East, there will be less precipitation but a much shallower and unstable snowpack. The northern portion of the zone may track closer to conditions in East North Zone. 

On Sunday, NWAC forecasters in the Icicle Creek area found 120-150cm of snow, and the 1/16 interface contained weak faceted grains and surface hoar. While this interface was becoming more stubborn, it still failed cleanly in tilt tests. They also found that the Solstice Crust still showed a propensity for propagation in snowpack tests. This weak snowpack structure is widespread throughout the zone but buried deeper in areas further west and north and becoming much more difficult to trigger. It is still likely to trigger an avalanche on this layer in areas where it is buried shallowly, like the Wenatchee Mountains. Dig down and find this firm crust with overlaying weak snow. You're more likely to trigger avalanches where this layer is buried closer to the surface. 

The Solstice Crust in the Wenatchee Mountains has been active since late December and continues to produce avalanches. Human triggered avalanches on this persistent weak layer have occurred on Jan 6th, 12th, 15th, 19th, and 20th. On Saturday in nearby East South, a rider remotely triggered an avalanche near Manastash Ridge that we suspect ran on the Solstice Crust. While these avalanches have primarily occurred in wind-loaded terrain, we can't rule out triggering avalanches in sheltered areas, especially as we add more snow to this weak snowpack structure. 

If you get out, let us know what you see by submitting a public observation!

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