Bollettino valanghe

West Slopes North

Northwest Avalanche Center
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Pericolo valanghe

Wed
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
3 · Marcato
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In sintesi

Expect a peak in avalanche activity very early in the morning when the bulk of the precipitation and wind arrive. Snowfall intensity will probably slow as the day progresses, but given the large amounts we just received, Tuesday is a good day to keep travel plans simple and stick to lower-angle, sheltered terrain. Dry snow avalanches that could bury and kill you are your main concern where you encounter several inches or more of new, dry snow, but where moist snow exists down lower, smaller wet avalanches could also happen. 

Problemi valanghivi

  • Storm Slabs

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

    Overnight and into the morning, plan on heavy snow and strong winds. Peak avalanche activity will likely be early morning, and you can expect that some natural avalanches may run. Snowfall and wind will back off as the day progresses. Stability will improve as snowfall rates and winds slow, but it's still likely that you can trigger a large slab avalanche that could bury and kill you on steep slopes. If snowfall stays heavy, danger may be higher and natural activity could continue. 

    Snow will be more reactive in thicker, wind-drifted slabs, and we expect a lot of slopes, especially at higher elevations, will be wind-affected. Even in sheltered spots, however, enough new snow exists that you could trigger and get caught in a large avalanche. 

    Today's a day to keep it simple: avoid traveling on steep slopes greater than 35° and stick to sheltered, lower-angle terrain. If you see natural avalanches happening, then stay away from lower-angle slopes beneath large, steep avalanche paths as well. This is a day to avoid traveling near terrain traps, such as areas above cliffs, large boulders, or trees. Don't find yourself in an area where if you're caught in an avalanche, you'll be funneled down into a gully and buried deeply. 

    Example photo: It's likely the you can trigger a large avalanche like this one on Tuesday.

  • Loose Wet

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

    Most wet avalanche activity will probably be near the top of the lower elevation band, where there may be several inches of moist new snow and fluctuating temperatures. We don't expect much wet activity in the older snow that's already been through extensive wetting. 

    Where new snow is moist or sticky, search for natural activity like rollerballs or small wet slides fanning out. If you see rollerballs and any wet loose slides, avoid similar steep slopes and the terrain beneath them.  You might be able to trigger a wet loose avalanche on a steep slope in moist snow as well. You might be caught by surprise if you trigger one and end up in its' sluff. 

    Example photo: Wet loose avalanche activity like you might see on Tuesday at lower elevations.

    Photo: Zack McGill - Cascade Mountain Ascents

Avalanche Discussion

We're expecting around a foot of snow overnight, and then earlier in the day we might receive around half that much again. Forecast models vary widely, so if snowfall continues heavily through the day, danger could be higher. 

The weekend's atmospheric river totaled about 4 inches of water, with the tail end of that finishing as snow, especially at higher elevations. When visibility improved, we saw several large (D2-2.5) wet slab avalanches and a few very large (D3-3.5) that stepped down into deeper, old snow layers that ran the full path, down towards valley bottoms. Wetting appeared to mainly affect the top 1-2ft of snow at mid and upper elevations, impacting less of the snow depth than we expected.

Another inch of water, probably around a foot of snow at upper elevations, fell early Sunday night. We had a break from precipitation during the day on Monday before the next stormy period arrives Monday night. After our last burst of precipitation Tuesday, the faucet will slow for a few days and temperatures will begin to climb. 

Regioni coperte