Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

Fri
Alpine
2 · Moderate
Treeline
1 · Low
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Out of date — this forecast expired 3 years ago.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

Look out for slabs of recently wind drifted snow in the alpine. You are most likely to trigger one on steep, convex terrain features or above and around cliffs. Use extra caution on steep wind loaded slopes with rocks, cliffs, gullies, or other hazards in the runout.

Avalanche problems

  • Wind Slabs

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

    The last bastion of avalanche danger is upper elevation terrain holding wind slabs. They formed with strong easterly winds Tuesday. While some subzones like Schriebers/Baker NRA and alpine terrain in North Cascades NP got hammered, other areas saw way less wind and have lower danger. 

    Wind slabs are getting difficult to trigger and will be even more so Thursday. On the other hand, some slabs are pretty deep to the point even a small avalanche could be damaging if you manage to find one. 

    Stiff wind slabs are difficult to assess with the usual tools like hand pits, etc. They also tend to release suddenly. Look for areas where the snow surface is smoother and surrounded by wind-hammered snow - they should be pretty easy to spot. Best policy might just be to avoid the few places you might trigger one.

     

    (3/29/2023)

    Natural slab avalanche that released with heavy wind loading on Tuesday. Wind loaded terrain was easy to identify after the wind event. If a slope had a south or west aspect, was not crusty or tracked, and had a relatively smooth surface it held wind slab. 

Avalanche Discussion

It appears wet loose avalanches have played themselves out for the time being. Thursday will bring slightly cooler temperatures, increasing clouds, and some wind ahead of a storm this weekend. There is still an outside chance you could see wet avalanche activity or even a glide avalanche anywhere the day starts warm and sunny. Pay attention to slopes overhead.

While backcountry travel is at a low point between storms, some folks are still getting out and enjoying the sun. An NWAC Forecaster at Schriebers/Baker NRA found a number of small but deep wind slab avalanches on west aspects above treeline. They occurred naturally with strong winds and rapid loading Tuesday and released above a sun crust that formed over the weekend and Monday. They didn’t show much reactivity in testing but one slab sticking to a very steep  breakover produced a whumph when approached from the side.

Triggering an avalanche in a layer of weak facets and surface hoar buried in the last storm is unlikely. But unlikely isn’t impossible so don’t ignore obvious signs of instability like whumphing or shooting cracks if you find one of the rare places the setup still exists. Sheltered, northerly terrain is where this layer might still be hanging on under snow from the last storm.

 

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