Bollettino valanghe

Snoqualmie Pass

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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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Friday should be a relatively warmer day between pulses of colder snow-producing storms. Keep an eye on the recent storm snow to see if the springtime weather is producing fresh rollerballs or fan-shaped avalanche debris. If you notice these signs and the snow is wet and sticky, consider avoiding slopes over 35 degrees.  

Problemi valanghivi

  • Loose Wet

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

    Even with mostly cloudy skies, warmer temperatures and breaks of sunshine could be enough to weaken the new storm snow enough to produce Wet Loose avalanches on Friday. If you notice that the snow surface is getting wet and sticky or see early signs of wet avalanches such as rollerballs and pinwheels, then you’ll know it's time to consider avoiding steeper slopes where these avalanches are more likely. Slides should be larger the higher you ascend in elevation due to more storm snow being available to slide on the 3/30 crust. Don’t get caught off guard by one of these slow-moving but powerful avalanches near terrain traps or other consequential terrain. They like to fan out as they descend downhill and are capable of entraining snow and growing in size. 

    In some locations, you might see a cornice collapse or block of snow fall off rocky terrain due to the warm temperatures. Be cognizant of what’s above you and give a wide berth to these ticking time bombs.

    (3/28/2022)

    In this image you can see several of the current spring avalanche concerns. 

    Photo: Dallas Glass

Avalanche Discussion

At least for a day, we returned to something resembling winter at Snoqualmie Pass. Up to 10” of storm snow fell at upper elevations and was found to be well bonded to the underlying 3/30 crust by both NWAC forecasters and Alpental Pro Patrol on Thursday.  Accumulations vary based on elevation and tree cover, as did the thickness and firmness of the 3/30 crust. This new snow will only be fuel for wet avalanches during the upcoming warmer day on Friday. It may take a few hours for the snowpack to warm up and reach the threshold for wet slides, meaning hazard could increase throughout the day. That doesn’t mean that things will be “safe” first thing in the morning. You should still be thinking about avalanches in the new snow like Dry Loose running on the underlying crust, or isolated Wind Slabs at upper elevations near ridgelines or confined chutes and gullies. As temperatures warm throughout the day, these problems should diminish, with northerly aspects likely the last to hold onto cold dry snow before transitioning to wet and sticky.

Below the 3/30 interface, there is a very springlike snowpack with large meltforms and thin melt-freeze crusts. We don't anticipate many avalanches making it down into these layers on Friday, but can’t rule out an isolated incident resulting from a very large trigger. As you look deeper in the snowpack, you’ll find the easily identifiable Early March Crust anywhere from 2-3 feet below the surface.

Regioni coperte