Bollettino valanghe

East Slopes North

Northwest Avalanche Center
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Pericolo valanghe

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

You may be able to trigger wet avalanches on steep slopes where snow surfaces are wet and weak. Mild temperatures and sun will keep snow moist following Wednesday's rain.

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    You may be able to trigger wet avalanches on slopes over 35 degrees especially where the sun melts the surface snow. Some of these could be large and dangerous. If you find wet, unsupportive snow, move to lower angle terrain and make sure to stay out from under steep slopes. Watch for rollerballs, pinwheels, and recent wet avalanches as indicators of the danger.

    A previously dry upper snowpack got wet from rain on Wednesday. Rain reached all but the highest elevations. Surfaces may freeze on Thursday night, though temperature inversions could make it tricky to anticipate which slopes will be solidly frozen.

    (11/29/2021)

    An example of rollerballs from a rain event on from 11/28. Slate Lake, SE

    Photo: Josh Hirshberg

Avalanche Discussion

Wednesday was a wet and rainy day with no new field observations. On Tuesday, observers reported widespread shallow (5-8") storm slab avalanches in dense new snow. Prior to the storm, observers found a variety of snow surfaces including thin surface hoar, sun crusts, and decomposing snowflakes. On, Monday observers reported a rain crust about 8" below the surface that exists below 5,300ft and roughly west of Delancey Ridge. 

A significant winter storm wrapped up on the 7th. In the Highway 20 corridor observers noted a widespread cycle with avalanches up to D2.5.  Slab avalanches were reported at low elevations in the eastern part of the zone. An even more widespread cycle occurred at lower elevations and in sagebrush country in the East Central zone, including in places like along Hwy 97A above the Columbia River.  From January 5-7th, the Washington Pass area picked up roughly 3.3 inches of water with 2' of settling storm snow.  Mazama saw 18" over this period.  The storm ended with extreme westerly winds that transported significant snow at all elevations on the 7th and 8th.  

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