Avalanche forecast

West Slopes Central

Northwest Avalanche Center
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Avalanche danger

Sun
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 8 months ago. You’re viewing past conditions, not the current bulletin.

Highlights

We'll get rain to upper elevations, but snowlines will slowly lower during the day. Your main concern is wet avalanches, where sticky snow and rollerballs are indicators that wet avalanches could happen, so steer around steep slopes or similar nearby areas where you see this happening. If you make it to upper elevations, stick to sheltered, lower-angle terrain if you find new drifts greater than 6 inches deep. 

Avalanche problems

  • Loose Wet

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

    Fresh new snow that's still damp is where  you might see wet avalanche activity. Alternatively, an underlying moist layer beneath new snow could initiate combo wet/dry slide, which you'd probably find in the mid elevation band. There may not be much for natural activity, but if you venture out onto steep slopes, you might be able to trigger a slide. In this situation, stay aware of your surroundings, and if you trigger a slide, move off to the side of the slope before it catches you. If you see any rollerballs or wet slides coming down, steer around areas where this activity is happening or similar slopes.

    Wet avalanche activity has been on the radar for days now.  Most old snow has already gotten wet and is probably less likely to slide, although it's not completely out of the question. This would probably be more likely on north-facing aspects, where there has been less of a transition to melt forms that on the sunny south-facing slopes. 

    Example photo: Rollerballs initiating from trees and other steep, rocky areas. These are indicators that more wet avalanche activity could follow. 

  • Wind Slabs

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

    If you make it to upper elevations, newly formed wind slabs could be 6 inches to a foot or more deep. Search out these fresh drifts and steer around them on steep slopes, as they could avalanche with a human trigger.

    You can identify new drifts because they usually have either pillow-like or textured surfaces. They tend to form around rocky outcroppings, along ridgelines, and on the sides of gullies and rollovers. Pay attention to areas of thicker, denser snow, and watch for red flags like shooting cracks. Simple hand pits can help assess how well wind slabs or new snow are bonding to the underlying snowpack. Avoid steep slopes where you observe any of these warning signs.

    Example photo: Wind transport creates obvious cornices. It' may not be as easy to see new wind slabs building up on slopes beneath the cornice, but expect them to be there. 

Avalanche Discussion

There's a lot of uncertainty in the weather forecast, never mind large variations with this incoming weather throughout the zone. Slight shifts in both precipitation numbers and freezing lines could make for different avalanche problems and danger levels. Because of this, be sure to evaluate conditions during your outing. Upper elevations could get about 6 inches of snow, whereas mid elevations will receive less, since much of the precipitation will fall as rain. 

Wet avalanche activity has been on the radar for days now.  Most old snow has already gotten wet and is probably less likely to slide. We hope that given the warm start to the storm will result in snow bonding well to the underlying layers. 

Regions covered