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 5 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Stay out from under cornices, unstable snow blocks in rugged terrain, and other overhead hazards that will persist until there is a significant decrease in temperature. Danger from wet avalanches may be higher on Saturday if there is more sun than expected.

 

Lawinenprobleme

  • Glide Cracks

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–3

    Observers on Friday reported numerous glide cracks and glide avalanches triggered by heavy rainfall earlier in the week. These avalanches occurred when the entire snowpack released on a smooth, steep ground surface below. Rain and meltwater lubricated and weakened the snow/ground interface to the point the snowpack could no longer hold in place. Glide cracks are areas where the slab is slipping on the ground but has not yet avalanched.

    The likelihood of more glide avalanches is very low with the end of rain and lowering freezing levels. It's difficult to say if these types of avalanches are really "Possible" since they are all isolated events by nature. Still, they have naturally released days after they were no longer thought to be a problem. This is especially the case with unsupported snow blocks hanging on the margins of the initial avalanche. Avoid traveling under sagging cornices, glide cracks, or areas where glide avalanches recently occurred. Give suspect terrain plenty of room and minimize the amount of time spent below if there are no other terrain options.

    (1/14/2022)

    Large glide avalanche or rock slab (just left of cetner) below Huntoon Point. Note hanging blocks, hangfire and sagging cornice all surrounding avalanche release area.

    Photo: Lee Lazzara

Avalanche Discussion

Besides overhead hazards, avalanche danger on Saturday will largely be determined by two factors. How much does the snow surface freeze overnight and how much sun comes out the following day? A cold night with a solid refreeze and lots of clouds will make the danger more lower as the snow surface will stay strong and locked up through the day. A weak refreeze plus more sun than expected means for a weak snow surface and might trigger another round of small natural avalanches on southerly aspects.

Wind transport of dry snow was observed at the highest elevations today. If you make it to the alpine on Saturday be on the lookout for small but unstable wind slabs in exposed terrain.

Excellent visibility allowed for observations throughout the zone. Glide avalanches, cornice fall triggered slab avalanches, loose wet, wet slab, and a very, very large slab avalanche high on Mt. Shuskan were reported. All were triggered during periods of warm temperatures and heavy precipitation earlier in the week. A round of natural loose wet avalanches with afternoon clearing was observed in steep southerly terrain above treeline on peaks north of Highway 542.

The snowpack is capped with a ski supportable crust. Below are alternating layers of wet rounded grains and melt forms down 60cm to a decomposing melt freeze crust. The latter formed from rain between periods of snowfall on January 6th. All layers were observed to be well bonded.

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