Avalanche forecast

East Slopes Central

Northwest Avalanche Center
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Avalanche danger

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

You could trigger an avalanche where stiff wind drifted slabs rest over weak snow. These avalanches could step down to more deeply buried weak layers, becoming very large and breaking across terrain features. Choose lower angle or sheltered terrain to avoid triggering one of these surprising avalanches. 

Avalanche problems

  • Wind Slabs

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

    While the storm slabs were much more stubborn on Friday, areas where the wind drifted snow still harbored reactive wind slabs. These stiff wind slabs formed over weak faceted snow and can take longer to heal. You are most likely to trigger these lingering wind slabs at mid and upper elevations below the lee side of ridges, the base of cliffs, or confined terrain features. Use visual clues to identify wind-loaded terrain, such as cornices or drifts around rocks and trees. Look for signs of instability, like recent avalanches or shooting cracks, as a warning to stick to lower-angle terrain. While the immediate concern will be for triggering avalanches in these aging wind slabs, don't rule out much larger avalanches. Seek out sheltered terrain to reduce your likelihood of a small wind slab stepping down to deeper layers and triggering a surprisingly large avalanche. 

    (1/19/2024)

    These sculpted features are a sign that the winds drifted the snow into stiff slabs where you could trigger an avalanche. 

    Photo: Katie Warren

  • Persistent Slabs

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

    These lingering persistent slab problems take a lot of patience to manage. While they could be trending towards more difficult to trigger, the consequences would be dire. Use conservative terrain management to avoid triggering one of these very large avalanches. Keep a wide buffer between where you travel and large avalanche paths. Only expose one person at a time to avalanche terrain. Avoid wind-loaded steep terrain where a smaller avalanche could step down to these deeper weak layers. A complicated and problematic snowpack structure exists, and some suspiciously large or deep avalanches have been observed in East Central. We anticipate these avalanches are becoming harder to trigger in some areas of the zone, but they may be more likely in the Wenatchee Mountains, where they lurk closer to the surface. If you got unlucky and hit the right spot, these avalanches could be 2-4 ft thick and propagate widely across terrain features. It's not time to let your guard down yet. Steer clear of large avalanche paths while we gain more confidence in the reactivity and distribution of this problem. 

    (1/19/2024)

    Remotely triggered avalanche near Blewett Pass on January 19th. 1-2ft deep and 30-50ft across. 

Avalanche Discussion

Some areas of the zone harbor more dangerous avalanche conditions. Further East and South, weak structure and evidence of large avalanches keep us suspect of large, steep, open slopes. Further North and West, conditions seem to be settling out. That being said, we don't have much information from upper elevations since this stormy period. Build that increased uncertainty into your travel plans, giving yourself more time to make observations and wider terrain margins.

A mixed bag of precipitation hit the area on Friday, and some areas now have a candy coating of ice from freezing rain on the snow surface or a new melt-freeze crust from liquid water. We're still in a transition back to wetter and warmer weather. As we step out into the mountains after these big shifts, be prepared to make assessments as you travel, and don't be surprised to see strange or quickly changing conditions. 

Speaking of wetter and warmer, you may see a few rollerballs or small wet loose avalanches in steep terrain on Saturday. These could be more widespread if the sun comes out, but we don't think it will become a problem. 

The Wenatchee Mountains have a shallower, weaker snowpack, and observers reported sudden, easy failures in snowpack tests on old December facets. Backcountry travelers have continued to report notable signs of instability, such as collapses and propagating test results. I was out in the Teanaway Drainage on Friday, and while visibility was limited, we could see what looked like a widely propagating avalanche and a smaller but deep avalanche. Both of these were in wind-loaded terrain across the valley. Wind slabs were still reactive on the recent 1/16 interface, and the 1/8 melt-freeze crust produced propagating test results. 

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

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