Avalanche forecast

East Slopes Central

Northwest Avalanche Center
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Avalanche danger

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

We're stuck in a repeating weather pattern, bringing recurring avalanche conditions. You could trigger avalanches in wind-drifted snow at mid and upper elevations. Most avalanches may be small in shallow fresh drifts, but there is potential to trigger a large avalanche that breaks 2-3ft deep in older wind drifts. Reduce your uncertainty by steering around steep slopes with stiff wind-textured snow. 

Avalanche problems

  • Wind Slabs

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

    Wind slabs are becoming more stubborn to trigger with time. However, in some areas, these stiff wind slabs formed over weak snow layers that take longer to strengthen, and you could still trigger a large, hard slab avalanche. A few inches of fresh snow and another day of easterly winds also means you could find shallow new drifts to trigger a small avalanche. Winds have blown in multiple directions over the last few days, so look for wind slabs on various aspects or even mid-slope. Strong winds have pressed these slabs into firmer 1F-P hard slabs in exposed alpine terrain. Consider the high consequences of triggering a wind slab that breaks wider and deeper than expected if it fails on weak snow above the Early February Crust. 

    Use visual clues such as blowing snow and textured surfaces to help you identify where the wind slabs may lurk. Be suspect of terrain features that encourage drifting, such as the leeward sides of ridgelines, alpine couloirs, gully features, and cross-loaded depressions. Dial it back if you notice shooting cracks, whumphs, or hollow-sounding snow. 

    (2/18/2024)

    Triggering a wind slab in the wrong spot could result in a much larger and wider avalanche if it breaks on old snow above the Early February Crust. 

    Forecasters observed this 1-2 day-old avalanche in the Teanaway drainage on Sunday. 

    W aspect, 6200 ft

    Photo: Katie Warren

Avalanche Discussion

This repetitive weather pattern is scheduled again for Tuesday. You'll see a couple of inches of fresh snow and a return to easterly winds. The only notable difference is that temperatures will be slightly warmer, and you could see a round of rollerballs or small wet loose avalanches. Although you could get a few sucker holes with the sun poking out, we don't expect they will be long-lived. With this pattern, we are incrementally loading weak snow layers both in sheltered and wind-drifted terrain, where slabs are much thicker and more dangerous. In terrain sheltered from the wind, this snow lacks the slab-like characteristics to produce an avalanche, but this is beginning to change with the continued trickle-in of snow. Anywhere you find more than 8 inches of snow above a stout crust or see wind-textured surfaces could be problematic. These slabs may not be that deep but could be large enough to ruin your day if they propagate widely on well-developed facets over a crust. 

The Wenatchee Mountains and other drainages in the southern reaches of the zone received 10-16" of recent snow. Initially, the new snow fell very cold and low density. However, recent warm temperatures are consolidating the surface snow to form a more cohesive slab. This slab may rest over weak, faceted grains or surface hoar associated with the Early February Crust (EFC) or a sun crust on southern aspects. This hasn't become a widespread problem yet, but we have quite a lot of uncertainty with the sensitivity and distribution of this avalanche problem. But, since February 15th, 13 unintentionally human-triggered avalanches have failed on or just above the EFC throughout the Washington Cascades. Most of these avalanches have been between 5000ft and 8000ft and cover all aspects. Thankfully, no one was injured in these incidents, but this is critical information that this weak layer can still produce avalanches. It is best to stick to sheltered terrain or low-angle, well-supported slopes while the weather keeps giving us windy conditions along with dribs and drabs of snow. 

On Sunday, we traveled into the Teanaway Drainage and found plentiful wind-affected surfaces and warming temperatures. We observed an old wind slab (W aspect, 6200 ft) that likely ran between the 15th and 17th of February and failed on weak facets on the Early February crust. This avalanche broke 3-4 deep and ran 300 ft. Lower elevations held little new snow, and warming temperatures may have developed a new melt-freeze crust on surfaces up to 6000ft in this area. 

Earlier in the weekend, a group of skiers near Ingalls Peak in the Teanaway had a close call and triggered a small soft slab in wind-drifted snow. The skier was able to arrest on the bed surface as the avalanche failed. This avalanche occurred on a south aspect at 5500 ft. You can check out the complete avalanche observation here. 

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