Lawinenlagebericht

East Slopes Central

Northwest Avalanche Center
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Lawinengefahr

Tue
Hochgebirge
2 · Mässig
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

It may be possible to trigger avalanches in areas where the wind has deposited snow into deep drifts.  These slabs may dwell in alpine areas, near ridges, or wind-exposed slopes at lower elevations. Navigate around steep slopes in wind-affected terrain.

Lawinenprobleme

  • Wind Slabs

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

    Strong winds during the storm on December 18th built wind slabs on various aspects and possibly in unsuspecting locations near and below treeline. It will still be possible to trigger these lingering slabs. Travel cautiously in open terrain, especially near ridges in upper elevations. Shooting cracks, stiff or hollow feeling snow, and collapsing are all signs you should stick to low-angle slopes and choose conservative terrain. 

    These stiff wind slabs are likely resting on soft storm snow from the previous week. The snowpack has had a day of cold temps, settlement, and light wind to adjust to the recent load. These slabs may now be stubborn to trigger, but there is still the possibility of triggering avalanches large enough to bury or kill you, especially in very steep terrain. Use your pole, probe, or hand pits to identify areas of stiff snow over soft snow and observe how easily the stiff upper snow slides on the underlying surface. 

    (12/16/2021) Hand pits are a great way to investigate snowpack layering and identify wind-loaded slopes.

    Photo: Katie Warren

Avalanche Discussion

After a significant storm and natural avalanche cycle on Saturday, the Central Cascades enjoyed a relatively mild day on Sunday, with cold temps and even clear skies in many areas. The mellow weather allowed for 3-4” settlement in the new storm snow from December 18th.  Areas in wind-sheltered terrain, especially in lower elevations, are decreasing in danger, and observers are finding a favorable, right-side-up snowpack. You still have the potential to trigger avalanches in wind-loaded areas. If you are traveling in wind-affected areas such as ridgelines or open slopes, pay close attention to changes in the snow beneath you. Differences in texture, stiffness, and depth will indicate that you are stepping into wind-affected areas, and you should steer around steep terrain and steep convex rollovers. 

We have limited data from elevations above treeline and in the northern portion of the zone. In some areas, weak snow may exist above crusts, creating the potential for larger avalanches, approach complex or large terrain cautiously. Use snowpack tests to determine how well bonded the overlying snow is to these crusts.

There is a lot of variability throughout the zone, and a more substantial snowpack exists in the western portions. Winds have built slabs on lee aspects even in the eastern parts of the zone that lack a substantial snowpack. Expect the avalanche danger to differ throughout the zone, and stability on one slope may not represent adjacent slopes. 

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