Bollettino valanghe

West Slopes South

Northwest Avalanche Center
Vedi sulla mappa

Pericolo valanghe

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

In sintesi

Expect dangerous avalanche conditions, particularly near the volcanoes where significant snowfall is forecast. Avalanches will be more likely during and immediately following periods of heavy snowfall. They may look inviting, but avoid steep open slopes. 

Problemi valanghivi

  • Storm Slabs

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

    A lot of snow is expected by Sunday morning. Even though this storm followed cooling temperatures, strong winds and heavy precipitation rates likely built weaklayers within the new snow. 

    Use hand pits, uptrack tests, and small slopes to check the bond to the old surface and look for inter-storm layers. Cracks, small avalanches, or blocks that slide easily all point toward unstable snow. In areas where you see deeper and firmer drifts avalanches could be much larger and might trigger more easily. Whenever you see any of these signs, avoid steep open slopes in nearby terrain. 

    We aren’t expecting a widespread avalanche cycle, but you could see a few natural slides occur. These will be most likely when it’s dumping snow or winds are forming big plumes along ridges. During these times, stay off of and out from under larger slopes.

    (12/8/2023)

    Example: Hand pits are a great way to look at the new storm snow. Look for strong over weak layers and places it fails easily. 

    Photo: Andy Harrington

Avalanche Discussion

With 2 feet or more of snow expected on Mt Rainer and Mt St Helens by Sunday afternoon, conditions could get really spicy. But, even the areas closer to the crest should pick up another foot or so of snow. This will be a welcomed sight following the recent warm weather and Saturday’s rain. 

On one level this forecast is straightforward. Significant snow and strong winds should result in dangerous conditions and the potential for natural and human-triggered avalanches. On the other, the other hand there are some lingering questions. 

-Rain reached well above our forecast elevations. This should have destroyed any nasty surface hoar or facets. However, Crystal Mountain didn’t see much rain. Even White Pass received less than anticipated. There’s a chance some of these weak grains survived above 5500ft.  In these areas, sudden test results, whumps, or collapses should all cause you to dial it back. 

-Stormy weather and limited visibility prevented much in the way of observations on Saturday. We don’t know the size and extent of any avalanche cycle. Look out for piles of frozen avalanche debris. 

-Potential glide avalanche concerns won’t stop on a dime. Even though it's snowing these slides could release. Avoid traveling under any crevasse like cracks in the snow. 

Lower-elevation snowpacks were thin prior to this storm, and the rain didn’t help. This should keep any potential avalanche small. However, there are lots of obstacles to hit. Even if covered with a fresh blanket of snow, there are some real hazards out there. Give yourself time and travel cautiously at lower elevations.

Regioni coperte