Bollettino valanghe

West Slopes North

Northwest Avalanche Center
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Pericolo valanghe

Thu
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 5 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Wind slabs both new and old can be found on a variety of aspects. Identify and steer around steep features with wind drifted snow to reduce the risk of triggering an avalanche. Be prepared for very cold temperatures on Wednesday.

Problemi valanghivi

  • Wind Slabs

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

    Differing vintages of wind slab can be found on just about every aspect in wind exposed terrain. Observers reported northeasterly winds drifting snow onto south and west aspects which created shallow, reactive new slabs. Though greater wind transport was observed high on Shuksan and nearby peaks, there was also enough transport near treeline to build scattered wind slabs.

    Older wind slabs from Saturday’s storm still exist on north and east aspects but became much less reactive to human triggers in the last two days.

    You will need to track the wind loading pattern in the surrounding terrain as you travel. Scoured snow surfaces, slabby-looking drifts, cornice features, changes in snow texture - pay attention to these and other clues to identify where both old and new wind slabs lurk. Use simple tests in safe areas to see how well these slabs are bonded to layers below - or simply bypass steep wind loaded features on lower angle, planar terrain

    (2/20/2022) Skier triggered slab avalanche on Huntoon Point in the Baker backcountry. This was an obviously wind-loaded rocky outcropping. Approximately 18" deep, 150ft wid. N, 5100ft.

    Photo: Pete Durr, USFS Backcountry Ranger 

Avalanche Discussion

Saturday’s storm put down 1-2” of precipitation across West North with 1' of new snow or more reported from most areas. Human triggered wind and storm slab avalanches to D1.5 were reported around the Baker BC (Artist Point, Table Mt.), Schriebers Meadow/Mt. Baker NRA and Canyon Creek over the holiday weekend. Small loose snow avalanches, natural and human triggered, were also observed on Sunday and Monday. They occurred on both shaded and sun exposed slopes. Very cold temperatures on Wednesday should keep loose wet avalanches in check though small loose dry avalanches should still be a consideration in very steep, shaded terrain.

In most areas, there is 1' of right-side-up new snow above a weak crust buried by the latest storm on February 19th. Drifts 2-3' deep were found in wind loaded locations above treeline. An annoying sun crust can be found on southerly aspects. Look for sun affected snow farther into direct east and west aspects as the late winter sun climbs higher in the sky. Crust-facet layering from late January can still be found 3' or deeper in shaded, alpine terrain but no new natural or human triggered avalanches associated with these layers have been reported in the last week.

 

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