Bollettino valanghe

West Slopes North

Northwest Avalanche Center
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Pericolo valanghe

Mon
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 2 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Be ready to see and maybe even trigger smaller avalanches. Stay off steep slopes holding wet snow over a crust or that are seeing direct sunshine. Investigate layers of dry snow at upper elevations before diving into avalanche terrain. Consider the avalanche danger a step higher and shift to simpler, lower-angle terrain if you observe widespread signs of natural or human-triggered avalanche activity.

Problemi valanghivi

  • Loose Wet

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

    Moist new snow over crust is primed to produce both natural and human-triggered avalanches on Sunday. Naturals are more likely on slopes seeing direct sun. You can trigger one on any steep slope where wet new snow overlies the old, crusty snow surface below. While the crust may not be frozen and slick, it’s firm enough for snow to slide on it easily.

    Keep an eye on terrain overhead and give some room to any steep slope seeing direct sun or where you observe rollerballs or small wet loose avalanches. Track how much snow is starting to move around you if descending steep slopes. Wet loose avalanches gained mass and momentum quickly on Saturday, and it would have been easy to get picked up and dragged down the hill if you weren’t paying attention. Or just stay off steep slopes with wet new snow over the crust.

    (4/12/2023)

    This is the kind of wet avalanche you could trigger on Sunday. While most will not be very big, they can still pack enough punch to knock you down and carry you downhill. They are even more dangerous with terrain traps like tress, rocks or gullies in the runout.

    Photo: NWAC Public Obs

  • Storm Slabs

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

    You might be able to trigger a slab avalanche in dry snow at upper elevations, especially farther west in the forecast zone, where more precipitation and snow fell on Saturday.  While you are more likely to trigger a slab in wind-loaded terrain, there is enough snow out there that it's worth investigating all aspects. Slabs can become more reactive when they get their first hit of sun.

    Use simple tests like slope cuts and hand shears to check the bond of any dry snow layers you find. Northerly winds could drift snow and create fresh slabs during the first half of the day. Avoid steep slopes where you observe active loading.

    (2/8/2023)

    You could trigger small slabs if traveling at upper elevations, or anywhere you find fresh layers of dry snow.

    Photo: Adam Ü

Avalanche Discussion

Chunks of cornice, pockets of snow clinging to steep rock, and glide avalanches are still things to look out for. These dangers are easy to identify and avoid as long as you are aware of what is directly overhead. These avalanches become more sporadic every day but the danger is still out there, and the consequences are high if you are in the way when one cuts loose.

Precipitation amounts on Saturday varied across the zone but in a less common pattern. Snotel sites near Baker Lake picked up about 1” of precipitation, while Heather Meadows saw about half that amount. The new snow was poorly bonded to the soft crust below. Small wet loose avalanches were easy to trigger, running fast and entraining all the new snow. No wind transport or fresh slab formation was observed. 

The snow level was observed at just below Heather Meadows at 4200’ but new snow didn’t really accumulate until 5000’s or so. There was about 4” of new snow at midday at upper elevations in the Baker BC. Expect to see anywhere from 4-10” on Sunday depending on where you head to in West North, with new snow amounts decreasing the farther east you travel in the zone.

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