Lawinenlagebericht

East Slopes North

Northwest Avalanche Center
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Lawinengefahr

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

Kernpunkte

Watch for signs of wind drifts above treeline to alert you to the lingering chance of wind slab avalanches.  Extremely cold temperatures will keep avalanches possible in light, dry surface snow on steep slopes. Bring plenty of warm clothes and watch for frostbite and other cold-weather injuries.

Lawinenprobleme

  • Wind Slabs

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

    Watch for triggering wind slab avalanches on the leeward sides of the highest ridges on slopes steeper than 35 degrees. Steer around areas of stiffer, drifted snow, deeper pillows, and wind features. There's significant uncertainty about the snowpack above treeline.  With lots of low-density snow available, slabs could form with lighter than usual winds. To avoid these avalanches stick to windward slopes or wind-sheltered and lower angled slopes. The eastern end of the Highway 20 corridor has seen little to no recent wind transport.

    (12/27/2021)

    The northerly aspects of the Cutthroat drainage with Cutthroat peak in the background. Low clouds hang around the ridges along with some possible wind transported snow. 

    Photo: Will Govus

  • Loose Dry

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

    With cold temperatures and existing light snow, you can trigger loose avalanches on slopes 40 degrees and steeper. Stop and regroup out from under slopes of concern. Terrain traps like cliffs, gullies, and trees can raise the consequences of avalanches that otherwise might not result in injury. Expect that avalanches could be larger at higher elevations. Watch for weakening snow surfaces from ongoing cold temperatures.

    Small Dry Loose avalanche in steep terrain near Dirtyface Mountain inthe neighboring East Central zone. Photo: Pat Riffie

Avalanche Discussion

Wednesday will be another relatively calm, cold day with some sun. This will be a great day to track the variety of surface conditions that have formed before they get buried by incoming snow on Thursday. Submit an observation and let us know what you see. This week, temperatures dropped to unusually frigid lows. Be diligent about keeping warm and preventing cold injuries like frostbite. With all the recent snow, watch for falling into tree wells and keep your partners in voice and visual contact.

On Monday, observers on Delancey ridge reported very calm conditions and light, dry snow. Some wind transport may have been visible on the highest ridges near the Cascade crest.  On Sunday, an observer on the eastern end of the Highway 20 corridor found 10cm of new snow over another 50cm of settled snow that has accumulated since the 21st. They reported generally, stable conditions with potential for loose avalanches in surface snow. 

At the interface that was buried around the solstice, observers reported finding surface hoar as well as a thin sun crust on steeper S-SW slopes.  Observers have reported that these layers generally haven't been problematic. The last widespread avalanche cycle occurred on Saturday, Dec 18th (up to size D2.5) in the Washington Pass area.  A crust buried in early December can now be found roughly 4-5 feet below the surface, especially on slopes near and above 6000 ft.  We haven't seen recent avalanche activity on this crust.  If you're in the mountains, you can contribute to the forecast by submitting an observation.

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