Bollettino valanghe

East Slopes North

Northwest Avalanche Center
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Pericolo valanghe

Mon
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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In sintesi

Dangerous avalanche conditions will develop as new snow accumulates on warming temperatures. Expect the most dangerous conditions in wind-loaded terrain, but still be suspicious of open, steep slopes that may harbor weak surfaces under the recent snow accumulations.  Sunday will be a good day to simplify your terrain selection and stick to lower-angled, sheltered terrain. 

Problemi valanghivi

  • Storm Slabs

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

    New snowfall accompanied by increasing snow levels are good ingredients for reactive storm slabs. Expect these slabs to be larger and more consequential across wind loaded terrain, but still be suspicious of any open slopes greater than 30 degrees as new snow piles up. In some areas, these storm slabs may trigger easily and break in surprising ways if they overload recently buried weak surfaces - like surface hoar or other faceted grains on a crust.

    Look for instability using test slopes, hand shears, and other simple tests. Snowpack collapsing or cracks shooting out from your feet or machine are obvious signs of instability that you should not ignore. When in doubt just stick to simpler, sheltered, lower-angle terrain.

    (1/4/2025)

    Surface Hoar grains buried 15cm deep in Cutthroat Drainage at 6700ft on a NE aspect. 

    Photo: Katie Warren

Avalanche Discussion

This won’t be a big storm for the East North, but some warming and uncertainty around the distribution of buried weak layers in the upper snowpack should help keep your terrain selection simple on Sunday. Snow levels are forecast to increase up to 4000 ft as the wind shifts more westerly, so this may result in some rain-on-snow and some small wet loose activity at lower elevations.

An NWAC forecaster reported finding a buried layer of surface hoar roughly 6 inches below the snow surface in the Silver Star area on Saturday. She found this layer reactive with compression tests and shovel tilt tests. Another avalanche professional working in the Cutthroat drainage also reported snowpack tests failing on a layer of weaker snow at similar depths.  

Before the recent increase in danger, observers reported isolated but lingering wind slab instability. On the 1st, a small wind slab avalanche (D1, NE, 6,392ft) was triggered in a basin southwest of Blue Lake. There have been reports of isolated cracking. Earlier this week, a large natural avalanche occurred on Poster/Pika Peak in unsupported, cornice-filled terrain. It may have stepped down into older, deeper layers. Observers on Silverstar Mountain reported significant wind-affected snow at upper elevations, but no signs of instability. Elsewhere, observers have found plenty of soft snow on the surface.

Snow totals throughout this past week are between 2-4 feet above 4000ft. Near Washington Pass, a thin crust buried around the Solstice can typically be found about 2 feet below the surface with snowpack depths averaging 5 feet.  In the foothills and eastern portion of the zone, you may find similar amounts of recent snow, but there may be more weak layers than at the Cascade crest.  Snow depths are roughly 2-3 feet. Pay attention to red flag signs of instability, such as whumping collapses, and consider digging down to identify potential weak layers.

You can contribute to the avalanche forecast. Please let us know what you see in the mountains by submitting an observation.

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