Bollettino valanghe

West Slopes South

Northwest Avalanche Center
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Pericolo valanghe

Tue
Alta quota
4 · Forte
Limite del bosco
4 · Forte
Sotto il limite
4 · Forte
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In sintesi

Very dangerous avalanche conditions will exist throughout the West South zone on Monday. Avalanches will be large enough to bury or kill you and this will not be a day to try to outsmart the hazard. It probably won’t be very pleasant out anyway, so may as well stay at home and let this storm run its course.

Problemi valanghivi

  • Wet Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Very Likely
    Dimensione
    2–3

    Very heavy precipitation, rapidly warming temperatures, and strong winds will all combine Monday to create very dangerous conditions around the West South zone. We expect lots of large natural avalanches big enough to kill you at all elevations. In some locations, these slides may entrain significant snow, break into older snow layers, and grow very large and destructive. Stay away from all avalanche terrain including where slides can run and stop. As temperatures creep ever higher, snow that maybe started the day as dry could quickly transition to wet as it is destabilized by heavy rain. While some of the resulting avalanches could be loose, many could be wet slabs. Truly it doesn’t matter, loose or slab, wet or storm; this isn’t a problem or day you want to try to tiptoe around. Keep away from all avalanche terrain until this storm plays out. 

    (1/7/2022)

    This very large avalanche was triggered by explosives on 1/7. More slides like this are not out of the realm of possibility over the next 48 hours. HS-AE-R4-D4-O, NE, 6800. 

    Photo: Crystal Mt Ski Patrol

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Very Likely
    Dimensione
    2–3

    Until rain reaches upper elevations, snow will be the predominant precipitation type. The upper reaches of the volcanoes may be able to elude the rain completely during this event, but there is some uncertainty about this possibility. Regardless, with the intensity of snowfall we are expecting, dry natural avalanches should occur anywhere snow is able to pile up. As was noted above, it doesn’t really matter how you want to characterize these avalanche problems. The high precipitation rates, wind, and warming temperatures should be enough for you to realize that Monday will be a very dangerous day to be in the mountains. Even your usual “safe” areas down in the trees could be suspect due to larger avalanches running from above. Stay out from where avalanches can start, run or stop.

    (1/9/2022)

    A very large avalanche from the January 6-7 cycle.  On the highest peaks or on the volcanoes, dry snow could persist and produce similar avalanches. [Pinnacle Peak NW 6200']

    Photo: NPS Rangers

Avalanche Discussion

On Sunday, the West South got its first taste of the warm weather that is set to impact the zone for the next 48 hours. Crystal Mountain Pro Patrol reported wet avalanches developing at lower elevations as temperatures started to creep up mid-day. This is just the first of several rounds of natural avalanche activity we are expecting by the time this storm has run its course on Tuesday. We should be in the storm’s bullseye on Monday, and we often talk about avalanches being more likely during periods of heavy precipitation or wind. Well, we are expecting significant snow at mid and upper elevations before quickly rising freezing levels allow the new snow to become soaked with heavy rain. The forecasted water numbers for Paradise (4.5” of water by end of day Monday) are stunning, but even areas closer to the crest will be getting enough significant precipitation that very dangerous avalanche conditions will exist. We expect to see both dry and wet slides throughout the zone and even in the same location. We believe that all the snow above the Valentine’s Day Crust is in play to fail given the right terrain, so slides could grow very large and run toward valley bottoms. Many avalanche paths have filled in and been greased throughout the winter, giving potential slides the ability to run full path. This helps drive very dangerous avalanche conditions even at lower elevations.

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