Lawinenlagebericht

West Slopes North

Northwest Avalanche Center
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Lawinengefahr

Sun
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

Avalanche danger will increase as you gain elevation. Look for and avoid steep terrain where you identify thicker slabs of recently wind-drifted snow. Use extra caution if you ascend into open, alpine terrain.

Lawinenprobleme

  • Wind Slabs

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

    At upper elevations, there was more new snow to drift into fresh slabs so bigger avalanches could be triggered on large, leeward terrain features. Pay attention to the pattern of wind loading by using scoured snow surfaces, cornice-like features, and changes in snow texture to figure out where wind slabs lurk. 

    You can track the depth of new and wind-drifted snow over the wet, crusty snow below. This can help you identify areas holding deeper new snow and wind slabs as you gain elevation and switch aspects.Use small test slopes to get a read on how the new snow is reacting to your weight. Small hand pits can show how well fresh slabs are bonded to moist snow or crust layers below.

    Observations from other zones indicated there is a good bond between the old, moist surface and the new snow that accumulated above.  Poorer bonding could be found where the new snow fell on a hard, frozen crust, but most slab avalanches should release within the new snow layers.

    (2/24/2023)

    Scoured surfaces like these above the small wind drifted feature can help you identify areas of wind slab.

    Photo: Zack McGill - Cascade Mountain Ascents

Avalanche Discussion

Temperatures are forecast to stay below freezing, but southerly aspects could see some sun warm the new snow in the afternoon. Pay attention to slopes overhead and look for initial signs of instability like snow shedding from trees and rocks, pinwheels or balls of snow rolling down the slope.

New snow amounts in West North likely ranged from 6-12” of new snow at mid and upper elevations. Lower elevations saw a trace to a few inches of new snow fall on bare ground. The Heather Meadows precipitation gauge was out for the morning but the Middle Fork Nooksack and Martin Ridge Snotels both showed 0.6” of precipitation as of Friday afternoon.

While the mountains should look more white and wintery on Saturday, the wet sponge of a snowpack sits not far below the new snow. A recent profile in mid-elevation terrain showed rain and melt-affected snow from surface to ground with some stronger crusts mixed in. The existing snowpack (below the new snow) is more reminiscent of a strong, fully-transitioned summer snowpack versus what we would see in a typical December.

The new snow will also just barely conceal a number of creek holes, rocks and even patches of bare ground that melted out in previous days. Old avalanche debris should also be on the checklist of non-avalanche hazards.

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