Lawinenlagebericht

East Slopes Central

Northwest Avalanche Center
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Lawinengefahr

Sun
Hochgebirge
2 · Mässig
Waldgrenze
1 · Gering
Unterhalb
1 · Gering
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Kernpunkte

While forecasted cooler air east of the Cascade Crest may help limit the extent of wet avalanches on Saturday, it still may be possible to trigger wet avalanches on steep sun-exposed terrain. You may be more likely to find unstable wet snow at upper elevations above the pool of cooler air. Expect challenging travel conditions depending on aspect, sun and wind exposure, and elevation. 

Lawinenprobleme

  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–1.5

    A strong inversion and east flow may keep lower elevations a little cooler than on Friday. But as temperatures warm and the inversion weakens in the afternoon, it may be possible to trigger small wet loose avalanches on steep sunny slopes. Upper elevations above the pool of cool air and easterly winds may be more susceptible to wet loose avalanches. There is significant variability throughout the terrain, so take time to observe the snow surfaces. If you see pinwheels or rollerballs or the snow feels wet and heavy, you might be able to trigger a wet loose avalanche. You can use short, steep test slopes to check if snow will move downhill. Steep slopes with moist snow in the sun are prime locations for wet loose avalanches to start.Be aware of overhead hazards and terrain traps that can increase the consequences of being caught in even a small avalanche. Many cornices have already failed, but those lingering may break off with another day of warm temperatures. Give these features a wide berth and avoid spending much time underneath them. If a large cornice breaks, it could trigger a wet loose avalanche on the slope below. 

    (2/9/2022) SE bowl of Big Slide Creek. Recent rollerballs and a small wet loose slide. Photo: Matt Primomo

Avalanche Discussion

The warm temperature trend continues on Saturday. The inversion in the forecast may weaken in the afternoon, and forecasted high temperatures are in the low 40°'s. With wet avalanche problems, monitoring changes in the surface conditions and weather throughout the day is important. Small terrain features form micro-scale weather patterns that can be substantially cooler or warmer than nearby locations. You can expect challenging and icy travel conditions in the morning and softened surfaces in the afternoon on sunny slopes. At the same time, shady slopes may harbor breakable crusts that might not soften without direct sunshine. 

From Jan 30- Feb 2, storms left over a foot of snow over various surfaces, including weak faceted snow and strong melt-freeze crusts. Strong ridgeline winds have since redistributed much of that new snow into dense slabs, scoured west aspects, and created stiff wind-board surfaces. Travel conditions range from thick supportable crusts, wind stiffened surfaces, breakable crusts, corn-like soft snow, manky wet snow, dry settled snow, and various degrees of in-between.

In some locations near the crest, weak faceted snow may exist above or beneath a crust from late January. We haven't seen avalanches on this layer yet in this zone, but an observer reported a very large collapse at 4,000ft near Eightmile Lake on Thursday. Observers continue to get whumphing collapses and shooting cracks in the East North zone. There is uncertainty on how this layer will react to the warming temperatures in the coming days. It is possible that a cornice failure or wet loose avalanche could trigger a deeper and surprisingly large slab avalanche. This layer is only 1-2ft deep, so you can dig down to identify and evaluate them. Look for weak, sugary snow over a firm melt-freeze crust. 

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