Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

Sat
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

A steady trickle of snow and light to moderate wind is expected to continue overnight and through the day, keeping avalanche danger elevated. You're most likely to trigger an avalanche in wind-drifted areas at higher elevations which saw more wind and heavier, thicker slabs are present. Steer around these wind-loaded locations on steep slopes. 

Avalanche problems

  • Wind Slabs

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

    Most wind slab avalanches you could trigger in steep, wind-loaded terrain will fail on or within the new snow layer. This is in the top 6 inches to foot or so of snow. Many avalanches will probably remain small, but some could be large enough to bury and kill you. Expect avalanche size and reactivity to increase as you gain elevation. Slabs are most likely to develop on leeward sides of ridges and steep rolls, on the sides of gullies, and around rocky outcroppings. Some could be hard and some very soft, or hidden beneath a non wind-affected layer. 

    Today is a good day to use test slopes and hand pits to investigate any weaknesses in the upper snow layers. Search for textured snow or pillowed features. You will probably notice yourself sinking in less on stiffer areas of snow, indicative of wind loading. If you see any recent avalanches or long shooting cracks these are red flags to steer clear of nearby steep slopes. Take all these factors into account and if you notice any of them, avoid slopes steeper than 35 degrees in the area. 

    A small avalanche which was skier triggered on a test slope in the Heather Meadows area. This is an old photo, but similar to what you might encounter on Friday. Photo: Pete Durr, USFS Backcountry Ranger

Avalanche Discussion

We've had a series of storms since Sunday, totaling around 2 inches of water, or 2 feet of snow, in much of the zone. Many subtle or not-so-subtle variations exist in the snow layers since Sunday depending on what mountain and aspect you're on. An example is that an observer found several inches of graupel falling in the Glacier Creek area on Thursday. This may be a short-term sliding layer for avalanches, and we don't expect it to be found everywhere. Most of the concerns earlier in the week have settled out relatively quickly, and the more recent layers of snow are the most reactive. It's not out of the question that in isolated locations which are probably wind loaded, an avalanche could fail 2-3 feet deep. 

Forecasts are showing us receiving a few inches overnight and another few inches during the day Friday. Temperatures will stay relatively cool, and light to moderate wind will sustain. Thanks to plenty of differences in the large West North zone, what you see will vary quite a bit, so use this avalanche forecast as a starting point for evaluating conditions where you're located. Danger may be slightly higher or lower than the forecast where you are. 

 

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