Bollettino valanghe

West Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

Thu
Alta quota
4 · Forte
Limite del bosco
3 · Marcato
Sotto il limite
3 · Marcato
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Non aggiornato — questo bollettino è scaduto 6 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Heavy snow, wind, and rain continue to stress the snowpack. Very dangerous avalanche conditions will remain at upper elevations over the next 24 hours. Be very suspicious of areas with wet unconsolidated snow, and build in a wide margin for error if you choose to venture out on Wednesday.

Problemi valanghivi

  • Storm Slabs

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

    Above the rain line,  several feet of new and wind drifted snow continue to overload the snowpack and maintain very dangerous conditions. Natural avalanches remain likely at upper elevations and could grow large enough to bury and destroy a car or break mature trees. This is a significant loading event and the snowpack needs time to adjust. Strong winds will continue to transport snow onto leeward slopes over the next 24 hours creating thicker and more reactive slabs. Cornices are likely growing large and may fall on slopes below acting as huge triggers. Avoid exposure to overhead hazard and seek out simple terrain away from areas where avalanches can start, run, or stop.

    (12/22/2020) Example photo of the crown of a very large slab avalanche in alpine terrain on the west face of Mt. Shuksan. Photo: Adam U

  • Glide Cracks

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

    Rain will continue to destabilize the snowpack Tuesday night, and wet avalanche concerns will still be an issue Wednesday. Wet avalanches could occur naturally and may act in surprising ways. Some uncertainty exists as to which type of wet avalanche will occur. Whether it be glide, wet loose, wet slab, or all three, conditions will be dangerous anywhere you find a wet unconsolidated snowpack. Heavy rain to 6500ft will continue Tuesday night, before temperatures cool Wednesday. Even when the rain stops or transitions to snow, the potential for glide avalanches will remain. The timing of these avalanches is challenging to predict, but they often occur during and immediately following significant wet weather events like this. Being caught in a wet avalanche Wednesday would likely have devastating consequences. Watch for areas of wet slushy snow or deep penetration and steer clear of traveling on or below terrain 35 degrees and steeper. 

    (1/3/2021) A very large glide crack below treeline in the Anderson/Watson area above Baker Lake. This glide crack opened during the rain event on January 1 when 3.5in of rain fell up to 5000ft. Photo: Tom Shields

Avalanche Discussion

A strong atmospheric river event will continue to bring a surge of moisture to the West Central Zone before conditions begin to dry out and cool off Wednesday. Another 2in of water expected Tuesday night will add to the impressive 6.5in+ water already received since Sunday. Numerous wet and dry snow avalanches were reported Tuesday in the adjacent Stevens Pass and West North zones. Storm slabs 12in thick released naturally and with human triggers in many areas. Wet loose avalanches grew large and entrained significant snow as they ran downslope. Expect the snow and avalanche conditions to be very different Wednesday at low and high elevations, with a nasty mix of wet and dry snow problems. 

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

Regioni coperte