Lawinenlagebericht

East Slopes Central

Northwest Avalanche Center
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Lawinengefahr

Sat
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist 3 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

New snow and strong ridgetop winds could create touchy new slabs near and above treeline. Look for signs of slab development such as active wind transport and deeply drifted pockets in exposed areas as you gain elevation. Use less steep terrain if you find signs of instability or more than 8" of new snow. 

Lawinenprobleme

  • Wind Slabs

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

    You'll probably find minimal danger at lower elevation, but conditions may change quickly higher up. Look for signs of active wind transport and drifted snow as you get higher in the terrain. Blowing snow and fresh cornice development are a few of them. You can also use surface textures like wind etching and rippling to help decipher areas that may act as a cohesive slab. Check for shooting cracks and use small test slopes to see how wind drifted snow may react before going into steep, wind exposed slopes. Slabs may react differently depending on the slope- Most slopes will have a frozen crust beneath the new snow, but shaded north facing slopes could hold dry, weaker snow underneath. 

    If you do find signs of instability, steer around more consequential terrain. 

    Rippled snow surfaces such as these indicate freshly drifted snow. Photo: Katie Warren

Avalanche Discussion

We're snapping back to winter Thursday night into Friday with much colder temperatures, strong ridgetop winds, and snow showers. Look for a solid freeze to form a supportable crust at lower elevations. Areas further south and near the crest stand to pick up more new snow than further north and east, so danger may be more elevated there. Beneath the new snow at higher elevations, most slopes besides NE-NW aspects should hold a crust from the recent sun and warm temperatures. On the shaded northerlies you can still find soft, powder snow beneath any new snow that falls. An observer on Wenatchee Mountain on Tuesday found somewhat reactive snow on shaded north facing slopes.

Over the last week, observers have reported numerous wet loose avalanches, and some isolated glide cracks. Some slides were large, so expect to find frozen debris in many areas hidden under the new snow. Any slopes with glide cracks should be avoided, as glide avalanches have been known to release a few days after temperatures have cooled. 

Deeper in the snowpack, you'll find intermittent sun crusts and a pair of rain crusts from Valentine's Day 3-5ft deep. This crust extends up to just below 7000ft with some weaker snow beneath it, and observations indicate wide variability in the structure and depth of this layer throughout the zone. Theres another crust which dates back to Martin Luther King Jr Day (Feb 12) down 4-6ft and extends to higher elevations. Very large avalanches that occurred on the 10th on Cannon Mountain, Rock Mountain, and North Chiwakum may have run on one of these crusts. For now, we don't expect to see more activity on these layers but theres a chance they could wake back up this spring with sustained warm temperatures or heavy rain/snow. 

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