Avalanche forecast

West Slopes Central

Northwest Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 3 years ago.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

Highlights

Say good-bye to spring-like weather and get ready for a round of wind, snow and cold temperatures. Avoid steep slopes with fresh, wind drifted snow as conditions deteriorate and the storm gains strength. Prepare for crusty, potentially challenging travel conditions at low elevations.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    The crux of the forecast is the timing between strong winds and new snow. There just isn’t much snow available for transport other than a few inches forecast to fall overnight. If snowfall picks up when the winds are still cranking Thursday, it won't take long for reactive slabs to build over slick crusts, weak facets, or both. Either way, the avalanche danger will be greatest at the end of the day.

    Areas of wind slab will be easy to identify. Look for drifting snow and smooth surfaces surrounded by old tracks, rollerballs, avalanche debris, etc. While the new slabs shouldn’t get very big, they might be more reactive than usual given the crusts and facets below them. 

    Bumpy old tracks are visible next to freshly wind drifted snow.

    Photo: Jason Speer

Avalanche Discussion

Glide and wet avalanches should still be on your radar despite colder temperatures. Glide avalanches have occurred days after it cools off. You could see rollerballs and small wet loose if sun breaks warm up freshly fallen snow. Also be on the lookout for glide cracks, avalanche debris, and any other hazards left over from melting, spring-like conditions. Dry new snow with the coming storms will start covering these but they will still lurk just under the surface.

Temperatures were in the 50's at some mountain weather stations around West Central with Snoqualmie Pass hitting a beachy 62 degrees.  The cycle of natural wet avalanches on the west slopes kept up its steady trickle with more glide avalanches and wet loose observed each day. Valley bottoms are slowly accumulating avalanche debris. Though the timing varied between forecast zones the message is the same:  prolonged warming after a month-plus of storms and cold snowfall makes the mountains fall apart. All you can do is stay out of the way. 

An NWAC Forecaster near Darrington found glide cracks and avalanches, sagging cornices, and other signs of warming in the surrounding mountains. They also found a surface crust on all aspects at and even above 5000'. An inch or two of new snow from a few days ago is faceted and found above the crust on shaded aspects. South facing slopes warmed nicely today and made for soft turns on a still-supportable crust at noon.

 

 

 

 

 

 

 

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