Bollettino valanghe

East Slopes North

Northwest Avalanche Center
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Pericolo valanghe

Wed
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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In sintesi

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

Problemi valanghivi

  • Loose Dry

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    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.

    We've received lots of recent, light snow, and the cold temperatures will continue to keep these avalanches a problem. Watch for weakening snow surfaces. We expect that avalanches could be larger at higher elevations.

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

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    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

Avalanche Discussion

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. 

Be diligent about keeping warm and preventing cold injuries like frostbite. We expect unusually frigid temperatures. Fortunately, winds will be light. Expect deep snow, difficult trail-breaking, and tree well/ suffocation hazards. Keep your partners in voice and visual contact.

New snow incrementally piled up since the winter solstice, with over 2' of settled storm totals in the Hwy 20 corridor.  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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