Bollettino valanghe

West Slopes South

Northwest Avalanche Center
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Pericolo valanghe

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

Winter-like conditions are expected to return to the West South over the weekend. Strong winds and cold snow should have you thinking about dry avalanche problems if you’re out in the mountains. You’re most likely to trigger an avalanche in wind-drifted snow so be on the lookout for these pockets to steer around.

Problemi valanghivi

  • Wind Slabs

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

    Wind speeds Friday night and Saturday should be strong enough to easily blow around newly fallen snow to create Wind Slabs for you to steer around. Look for these unstable pockets of snow to develop on the leeward side of ridgelines, convex features, or near rocky terrain such as confined chutes or the base of cliffs. As you travel, visual clues such as actively blowing snow, textured snow surfaces, newly forming cornices, or fresh drifts behind objects can help you identify terrain where Wind Slabs may have developed. If you notice that the snow feels firm and hollow or it looks smooth and pillow-like, then you may have found wind-affected terrain to avoid. 

    (4/2/2022) Look for visual clues as you travel to help anticipate possible wind slab locations. Photo: Dallas Glass

Avalanche Discussion

As of Friday afternoon, the winds are already ripping around the West South. NWAC’s station at Camp Muir has recorded multiple hours in a row with gusts over 100 mph, while other stations have had gusts anywhere from 40-60 mph. We don’t expect 100 mph winds to be the norm, but there should be speeds capable of moving snow throughout the forecast period. The question becomes: how much snow falls and is available for transport? 

A potent storm earlier this week had significant wind and dropped multiple feet of snow around the West South. This storm had us forecasting High hazard focused around dry avalanches for the first time in weeks. Shortly after the storm’s duration, temperatures soared on Wednesday and Thursday, producing wet avalanche activity more in line with April conditions and limiting the amount of new snow available for transport. A general cooling trend as we head into the weekend means that the wet snow surface should transition into a new melt-freeze crust (4/8). Snow this weekend is expected to bond fairly well initially to this crust and the majority of our avalanche concerns will be isolated to the newly fallen snow.

However, this is the springtime, and with that comes a lot of uncertainty around how the weather will play out. It doesn’t take much sun this time of year to tip the scales and start producing natural avalanches. If there are periods of sunshine throughout the day on Saturday, look for fresh rollerballs or snow shedding from trees and rocks as signs that small loose avalanches may follow. Depending on the duration of the sun, these could be dry or wet and run on the 4/8 crust. In isolated areas, a very large trigger could conceivably produce avalanches down to the Early April Crust, but this should be the exception rather than the rule this weekend.

Regioni coperte