Avalanche forecast

East Slopes Central

Northwest Avalanche Center
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Avalanche danger

Mon
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Large human triggered avalanches are possible on steep slopes near ridgetop, especially in the western half of the zone. Snow and strong winds have formed thick windslabs near and above treeline. Tread cautiously and give these newly created, firm slabs time to heal. Large persistent slab avalanches are becoming less likely, though still possible on isolated upper elevation terrain.

Avalanche problems

  • Wind Slabs

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

    Although the active wind drifting may have subsided by the time you get out there on Sunday, recently formed slabs will still be reactive to human triggering. Cohesive slabs rest over the most recent (12/21) melt freeze crust, and any avalanche may propagate wider and run further than expected because of it. Look for indicators such as shooting cracks and strong over weak layering with wind drifted snow. Use test slopes to check how well recent slabs are bonding. Avoid wind exposed slopes steeper than 35 degrees if you find signs of instability or fresh avalanches. Slabs will be deeper and widest in higher elevation, wind exposed terrain, and near ridgelines. You can avoid getting avalanched by seeking out sheltered slopes and terrain less than 35 degrees in angle.  

    (12/26/2020) Small windslab in the Wenatchee Mountains.

  • Persistent Slabs

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

    A Special Avalanche Bulletin is in effect for the neighboring East North zone due to lingering persistent slab instabilities. Persistent slab avalanches may still be triggered in the East Central zone, and could easily be large enough to bury or kill you. These dangerous and surprising avalanches can catch even the most experienced backcountry travelers. The added load of new snow and wind drifting may make triggering these deeper slides possible. With uncertainty about how easily you can trigger these avalanches, it's important to give them some time to heal. The best way to stay safe is to avoid where these avalanches exist. Keep your distance from slopes 35 degrees and steeper that are open enough and tall enough to produce large avalanches. Watch for obvious signs of instability like recent avalanches, whumphing collapses, or cracks shooting through the snow.

    Persistent slabs are more likely closer to the Cascade crest, in the western and northern portions of the zone. If you'll be traveling there, check out the neighboring Steven's Pass and East North zones. The most dangerous slopes will be at the highest elevations, where snow stayed mostly dry and where southwest to west wind drifted snow over the past few days. You can find a thin weak layer of small facets (and in places surface hoar) above a crust buried about 1.5-3 feet below the surface. 

    (12/23/2020) A crown of an avalanche that ran between Dec 19-20th on a NE aspect near 7,000ft in the Alpine Lakes Wilderness.

Avalanche Discussion

Some 4" of snow fell in the eastern half of the zone, but the higher peaks near the crest probably received closer to 8" of new snow on Saturday. Previous surfaces were a mix of slick melt freeze crust, near surface facets, and wind packed particles. There is uncertainty about how the new snow and windslabs are bonding to recent surfaces above treeline. Some sun may poke out on Sunday, and create potential for small loose wet avalanches on south facing slopes. In some areas and on steep slopes, the recent crust could still make for some slick and challenging travel.  

There is a lot of variability in snowpack depth just east of the crest where you may find 6ft of snow at 6000ft, but east of Highway 97 in the Wenatchee mountains you may only find a few feet at the same elevation.  

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources. Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

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