Bollettino valanghe

West Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

Mon
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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In sintesi

The level of avalanche danger will vary depending on where you are in the West Central forecast zone. Stormy conditions and rising danger will be found to the north, with significantly less snow and rain around and south of Hwy 2. Pay attention to changing weather conditions throughout the day and shift to simpler terrain as wind and snowfall increase.

Problemi valanghivi

  • Storm Slabs

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

    Snowfall amounts could vary greatly across West Central and end up being much more - or much less - than forecast. Look for 4-8” of new snow with higher amounts to the north and nearly nothing to the south. Wind speeds are more certain with strong to extreme winds reaching down into low elevation areas

    You will be much more likely to find an unstable slab on wind load slopes, but assess for instability in sheltered terrain as well. Slabs are more sensitive to triggering where they form over surface hoar or weak facets that have survived on shaded slopes.

    Start the day with an assessment mindset and test the waters with small slope cuts and hand pits before moving into bigger terrain. Be ready to find more instability in the afternoon than what was found in the morning. Stormy conditions might just keep you in the most sheltered areas for the entire day. 

    (12/8/2023)

    Unsupported, convex features like this are where you are more likely to trigger a slab avalanche.

    Photo: Alpental Pro Patrol

  • Loose Wet

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

    Rain will creep up in elevation overnight. It's forecast to continue before switching back to snow Sunday afternoon. Rain falling on fresh snow will increase the likelihood of seeing or triggering wet avalanches. 

    While any avalanches that do release should be small, they can still be consequential in low-elevation terrain with gullies, creeks, or other hazards in the runout. The first signs of wet avalanche instability would be snow shedding from trees, rollerballs, and very small avalanches.  Look for wet avalanches at mid-elevations if snow levels end up higher than forecast.

    (12/27/2023)

    Rollerballs initiating in steep and rocky terrain are an early sign of wet avalanche instability.

    Photo: Caya Johnson

Avalanche Discussion

West Central saw increasing winds and light precipitation on Saturday, with most weather stations recording 0.1-0.2" of precipitation. The White Chuck Tripod showed an inch of new snow and wind gusts up to 10mph. While this might not seem like much, it's sheltered location means it often shows significantly less wind than what is actually occurring.

Avalanche, snowpack, and weather factors were really, really different when comparing the zones to the north and south of West Central. A continuation of mild temperatures and low danger continued in the passes and West South. No avalanche activity was reported other than some fresh rollerballs and small wet loose avalanches around Snoqualmie Pass.

Full-on storm conditions were reported from West North with  6” of damp, wind-drifted snow and consistently strong winds. Reported avalanche activity was limited to very small wet loose avalanches and small slabs that tended to be stubborn to trigger. Signs of wind transport were widespread, even in normally sheltered areas. With poor visibility and challenging conditions, most stuck with smaller slopes instead of taking bigger avalanche terrain. No natural avalanches were reported, but no one could really see into areas that typically produce natural avalanches.

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