Bollettino valanghe

East Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

Fri
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In sintesi

Wet snow avalanches are a concern after a heavy rain event on Tuesday night. In the north and east ends of the zone, you could trigger a dry snow avalanche in wind-deposited snow. Use caution on slopes steeper than 35 degrees if you find signs of wet snow instability or cracking and collapsing in wind-affected terrain.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    It is possible to trigger a wind slab avalanche on slopes where dry snow exists and has loaded lee slopes. Rippled, uneven snow surfaces indicate that wind has transported snow, and soft, pillowy wind slabs may be lurking nearby. Hop on your skis or off your sled on small test slopes to check for instability before you hop onto steeper terrain. Shooting cracks and collapsing indicate that you have found an unstable slab. If you see signs of instability, stick to lower angle, wind-sheltered slopes.

    (12/12/2024)

    A small crown from skiers intentionally triggering wind-drifted snow on a steep slope. 

    Photo: Andy Harrington

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Wednesday night and Thursday will be warm. Combined with lingering moisture from the rain event Tuesday night, wet loose avalanches are a possibility. The typical progression of wet loose avalanches involves rollerballs and pinwheels that lead to point releases. Other signs that indicate warming are sticky snow surfaces, chunks of snow falling off trees, and water dripping from cliffs. Give sagging cornices a lot of space whether you’re above or below them. If the snow under your skis or sled is heavy and sloppy, keep to lower angle slopes or find terrain with a firm, supportable crust.

    (12/18/2024)

    A large pile of wet avalanche debris from natural avalanches at Alpental on the night of 12/17-12/18.

    Photo: Summit at Snoqualmie Pro Patrol

Avalanche Discussion

You will run into different conditions depending on where you are in the zone. For the north and east ends of the zone, the snowpack will be significantly cooler, having been less affected by the Tuesday night rain event. Mission Ridge Ski Resort reported dry snow avalanches at upper elevations in their control work on Wednesday. A few inches of new snow may fall on Thursday as well and get blown around. Where there is dry snow is where wind-affected snow can be found on Thursday.

In the west and south ends of the zone, the snow will more likely be wet at all elevations. Peak instability may have passed, but it can often take a few days for moisture to fade out of the snowpack. Wednesday night and Thursday weather will not speed up this process. Find supportable, refrozen crusts in these parts of the zone if you plan to get out.

Return to an early season terrain management mindset as you travel around. Rain could have re-exposed hazards such as rocks, open creeks, and trees that were previously buried under snow. Freezing rain that fell at lower elevations created a breakable “trap crust” that a sled will have no problem busting through but will test even the most skilled skiers. Give yourself the time and space to navigate variable conditions, no matter your elevation.

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