Lawinenlagebericht

East Slopes Central

Northwest Avalanche Center
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Lawinengefahr

Fri
Hochgebirge
3 · Erheblich
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist 5 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

New snow, cool temperatures, and strong winds are expected to create wind slab danger at upper elevations. Look for blowing snow, shooting cracks and fresh avalanches. Stay off of steep or unsupported slopes if you find evidence of instabilities. 

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1–2

    Stay on alert for signs of wind slab such as blowing snow, fresh drifts, and shooting cracks in freshly deposited snow. Strong winds during the day may quickly create wind slab hazard. You are most likely to run into this problem near and above treeline in exposed locations, such as the leeward sides of ridges and near rocky outcrops. Avalanches could also be larger at upper elevations, where there is more snow and drifts are deeper. 

    Steer around convex rolls and pillowed snow on steep slopes. Use test slopes to evaluate how the new snow is bonding as the day progresses. Stay off of steep slopes altogether if you find evidence of instability such as shooting cracks. Loose avalanches or sluffs may be worth considering in steeper terrain and during times of heavy snowfall.

     

    (12/19/2021)

    A crown from an avalanche (size D2.5) that ran on 12/18 in storm snow. Similar wind slab avalanches could occur on  Wednesday. Above treeline, NW, Chiwaukum range

    Photo: Matt Primomo

Avalanche Discussion

Anywhere from 1"-8" of new snow was reported on Wednesday, and more is on the way. Expect another round of snow, with greater accumulations into Thursday, but the temperatures should cool off markedly. Winds will begin moving the lower density snow, and lead to increased hazard in high, exposed areas. 

On Wednesday, Mission Ridge Ski Patrol found large (8mm) surface hoar growing over yesterday's melt-freeze crust near Lake Clara. We are uncertain the extent of this layer, but it's something to check for with quick hand pits over the next few days. Further west near Lake Wenatchee, an observer noted 8" of new snow sitting on this thin melt-freeze. The new snow had initially bonded well as temperatures were mild while the snow fell. 

The snowpack is generally strong and well settled near the crest, but very shallow and weaker in the Wenatchee Mountains near Mission Ridge. In these eastern most areas of the zone, basal facets (weaker snow) may be found near the ground. This weak structure may become problematic in the future with more new snow and heavy wind loading.

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