Bollettino valanghe

East Slopes Central

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

Exposed, downwind slopes will see some wind loading Thursday night and Friday. Cornices, riming, and rippled snow surfaces indicate wind transport, and blowing snow will point toward where slopes are being freshly loaded. Consider steering around steep terrain if you find these features and stick to lower-angle, wind-sheltered slopes if you encounter shooting cracks or collapsing.

Problemi valanghivi

  • Wind Slabs

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

    Anticipate new snow being blown around by wind speeds up to 25 mph. Larger slabs will exist in previously loaded areas; hard, uneven snow surfaces, rapid changes in snow depth, and cornices are good indicators of where these lee slopes are. There may be a layer of buried surface hoar within the snowpack and recently developed slabs will have formed over it. Surface hoar often appears as a thin grey line in a snowpit wall; you can dig a quick hand pit to check for it. Your biggest signs of instability will be blowing snow, shooting cracks, collapsing, and recent slab avalanches.

    (12/30/2024)

    This widely propagating avalanche in the Icicle Creek Drainage occurred overnight from December 29-30th. SS-N-D2.5-R3

Avalanche Discussion

The East Central zone should see up to 0.50" of water in the warm front impacting the zone. The expected moderate wind speeds are a bit more noteworthy, however. Typically, moderate wind is the prime transport speed for building wind slabs. So we expect new slabs to form, but some uncertainty lies with how well they will bond to themselves and layers below given the overall warmth of the system. Additionally, this storm will be more easterly and will blow snow onto slopes that have typically not been heavily loaded up until this point. If you have been getting out and finding wind loading on only north and east-facing slopes, don't be surprised if you encounter instability on a more west-facing slope.

If you see cracking or recent slab avalanches in lower elevation, wind-sheltered terrain, you have found some storm slab instability. There is a robust crust at lower elevations that could act as a slick sliding surface if enough snow falls on top and overloads the strength of the slab. Mark that as a sign to avoid steep slopes at all elevations.

We have minimal information about the lingering persistence and distribution of buried surface hoar. It was previously observed on the surface on all aspects at middle and upper elevations but observations have not called it out in snowpits. Surface hoar is a notoriously weak snow grain once buried, and my hackles are always raised if I know it may be lurking in the snowpack. Until we have more information regarding its presence, it would be a good idea to dig around and look for it before stepping into avalanche terrain.

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