Bollettino valanghe

West Slopes South

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

Wind slabs have been reported multiple days in a row in the West South zone. While none of them were large, you should keep these unstable pockets on your radar as you ascend in elevation. Due to an atypical wind direction, they could be in areas you’re not used to finding them.

Problemi valanghivi

  • Wind Slabs

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

    East winds capable of forming fresh wind slabs will return on Friday. The question becomes - how much snow is available for transport? Our hunch is that after several days of snowfall petering in, there should be enough to build slabs on leeward slopes. Look for them near ridgelines, the base of cliffs, or in confined chutes/gullies. Due to the atypical wind direction, they may form on aspects where you’re not used to seeing them, or slopes may be cross-loaded. Actively blowing snow, fresh cornices, or drifts behind objects can help you identify their locations.

    (12/28/2023)

    Fresh cornices on a ridgeline near Crystal Mountain. These visual clues can help you identify which direction the wind was blowing. Look for wind slabs to develop on the leeward slopes.

    Photo: Shane Robinson

Avalanche Discussion

We have received reports of wind slabs daily in the West South zone since Tuesday. All of them have come from the Crystal Mountain area. On Tuesday, an NWAC forecaster identified multiple wind slab avalanches, both natural and intentionally triggered. On Wednesday, Crystal Mountain Pro Patrol reported shooting cracks and slabs breaking up to 30 feet from ski tips while performing mitigation work. Come Thursday, avalanche professionals in the Crystal backcountry reported fresh cornices and small wind slabs near ridgeline during their travels. These slabs have been found on a variety of aspects.

We do not have observations from anywhere else in the zone this week. Those of you out snowmobiling, skiing, hiking, or whatever'ing in other areas, please let us know what you see by submitting an observation.

This week, we’re in a persistent pattern of shifting winds and light precipitation consisting of high-elevation snow and low-elevation drizzle. This will continue on Friday as the east winds kick back up. They shouldn’t be as strong as Wednesday but are expected to be powerful enough to move snow around and potentially create another round of slabs for you to avoid. You’ll likely encounter slopes stripped down to a frozen crust, pockets of wind-drifted snow, and areas of moist snow capable of producing rollerballs and small wet avalanches.

Despite some new snow and a more winter-like feel at upper elevations, natural hazards remain the story in many areas. That said, you can have a nice day out in the mountains by avoiding the open creeks, exposed rocks, and sometimes firm snow surfaces. 

Regioni coperte