Bollettino valanghe

Stevens Pass

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 will continue to stress the snowpack over the next 24 hours. Both wet and dry snow avalanches could grow very large. Be alert to changing snow and avalanche conditions with elevation and minimize exposure to overhead hazard.

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 even 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 growing and may fall on slopes below acting as huge triggers. Build in a wide margin for error and seek out simple terrain away from areas where avalanches can start, run, or stop.

    (1/12/2021) Numerous crowns from natural storm slab avalanches on the southeast slopes of Rock Mountain near 5400ft.

  • Loose Wet

    • 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. Look for signs of wet loose instability like rollerballs, wet sticky snow over dry snow, and recent fan-shaped avalanches. Avoid going underneath steep slopes, even if it's on a trail through the trees as wet loose slides could run through forested terrain. With all the recent precipitation, keep glide avalanches are your radar. Although hard to predict, they often occur during and immediately following significant wet weather events like this. Being caught in a wet avalanche Wednesday could 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. 

    (1/12/2021) A very large natural wet avalanche in the Wellington slide path near Stevens Pass. Photo: Will Govus

Avalanche Discussion

A widespread natural avalanche cycle occurred in the Stevens Pass zone Tuesday, with wet and dry snow avalanches in many areas. One very large avalanche ran naturally in the Wellington slide path, with a nasty debris pile gouging through the snowpack to ground. A strong atmospheric river event will continue to bring a surge of moisture to Stevens Pass before conditions begin to dry out and cool off Wednesday. Another 1.5-2in of water expected Tuesday night will add to the impressive water amounts already received since Monday. Expect the snow and avalanche conditions to be very different at low and high elevations, with the most dangerous conditions in wind loaded alpine terrain. The forecast comes with uncertainty about how the snowpack will respond to all the new precipitation. In any case, conditions will be dangerous to very dangerous, and travel in avalanche terrain is not advised on Wednesday.

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.

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