Avalanche forecast

West Slopes Central

Northwest Avalanche Center
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Avalanche danger

Fri
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 5 months ago. You’re viewing past conditions, not the current bulletin.

Highlights

Avoid steep slopes where you find recently wind-drifted snow. Convergence zone–enhanced snowfall may create more dangerous conditions between the southern Mt. Loop and I-90. Assess stability as you travel and default to lower-angle terrain to reduce uncertainty.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2

    Westerly winds should increase through the morning and will build fresh wind slabs on leeward slopes. When it's still blowing, wind-loaded slopes will be easier to identify - just take note of which slopes are accumulating drifting snow. As winds ease, use clues such as scoured surfaces, fresh drifts, and recently formed cornices to identify where slabs may have previously formed.

    While the primary hazard will be in wind-loaded terrain, don’t ignore areas with deeper new snow. Check how well the new snow is bonding to the old surface anywhere you find 6 inches or more of new snow. Slabs may be reactive even outside of obvious wind-loaded features.

    (1/29/2023)

    A shooting crack in wind drifted snow. Take a step back and avoid nearby steep slopes if you see signs like this. 

    Photo: Dallas Glass

Avalanche Discussion

Keep an eye out for snow shedding from trees, fresh rollerballs, and other signs of wet avalanche instability as the day warms. Clouds should keep the sun in check, but it’ll still be warm enough for snow to shed off cliffs and steep features, and trigger small avalanches on slopes below.

Conditions were indeed mixed today, with very different reports from the zones around West Central. Observers at upper elevations in West North found very strong winds, erratic wind loading patterns, and small but touchy wind slabs.  As the day progressed, similar conditions began to show up slightly lower as well. On the other hand, Low danger was still the name of the game in Stevens Pass. Snoqualmie Pass saw wind speeds increase throughout the day, likely pushing danger to moderate at upper elevations as the current storm approached.

West Central weather stations also showed a varied pattern, with lower-elevation sites picking up nearly a half-inch of precipitation overnight, while inland sites saw nearly none. Warm temperatures prevailed everywhere, so most precipitation fell as rain or very wet snow at mid elevations. Also of note is the very patchy snow cover at low elevations, as this NWAC Forecaster found on Tuesday.

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