Avalanche forecast

West Slopes Central

Northwest Avalanche Center
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Avalanche danger

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

We've begun an extreme warming period so beware of rapid snow and avalanche condition changes during your day. Wet avalanches are our largest concern, but at least they're fairly predictable: once you notice the snow getting wet or sliding downhill, it's time to shift to shadier or low-angle slopes away from steep start zones.  Wind-drifted snow may react to a human trigger, so steer around steep locations with thicker, wind-thickened drifts. 

Avalanche problems

  • Loose Wet

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

    Friday is the first official day of us really cooking. Freezing levels will transition from an unseasonable 10,000ft to 11,000ft during the day. Wet loose avalanche activity will start quickly as sun touches slopes, and you can expect slides to continue until the sun leaves a slope. The sun will first wet east-facing slopes in the morning, before shifting south and then on to west-facing terrain in the afternoon. Avalanche size will likely grow all day. A crust exists on most of these slopes from Thursday, but it probably won't take long for the sun to cook through that crust. 

    You may be able to travel really early on sunny aspects, but beware, as conditions can change very quickly. Small amounts of avalanche activity, or rollerballs, will be your first indicators before wet loose avalanches increase in size, probably becoming large and destructive. Slides will dig deeper into all the low-density snow that just fell. When you notice any of this activity, transition to shady aspects or away from any slopes greater than 30° and the runout beneath those slopes as well. 

    Wet loose avalanches may trigger slab avalanches as they pick up mass while traveling down a slope. Make sure you plan your day so you won't have to exit through terrain that earlier did not have avalanche activity but by the end of the day, could be very scary and active.

    Example photo: large wet loose avalanches like what you might see on Friday. 

  • Wind Slabs

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

    We suspect wind slab activity has slowed in the last day. These avalanches may be trending towards unlikely, but we have enough uncertainty that you shouldn't discount new or few-day old slabs completely. Some slabs could be shallow, only a couple inches deep, whereas others may be a foot or two deep. 

    Snow usually deposits below ridgelines, in gullies or around outcropping, features, and steep rollovers. Feel for stiffer slabs and search for textured, or rippled snow surfaces. The difference in heaviness may be subtle. Your weight on a wind slab may cause long shooting cracks. Steer around slopes greater than 35° where you identify wind loading, as you could trigger an avalanche resulting in a dangerous ride.

    (2/16/2024)

    Textured snow surfaces, indicating wind has been redistributing snow.

    Photo: Julz Holder - Grounding Truth

Avalanche Discussion

Neighboring zones have found areas where a weak surface hoar layer exists, buried beneath the storm snow that began falling on 3/9. It's not out of the question that sheltered locations at mid and upper locations, which didn't either get wind or see the sun, might harbor pockets of this weak layer, and resulting large avalanches could be triggered. 

We're in a stretch of very warm sunny weather. It will be the first big, spring-like warming event of the year, with high temperatures in the 50’s and freezing levels over 10,000’. Very warm conditions through the weekend could produce significant slab and loose snow avalanches.  As with any warming event, there is a high level of uncertainty as to where, when, or even if this scale of avalanche activity will occur. On the other hand, big natural avalanches aren’t really the kinds of things that should be taken lightly. It’s worth noting that smaller wet loose or wind slab avalanches, cornice falls, or snow shedding from cliffs can provide the trigger needed to pull out a very large avalanche. When planning for the weekend, consider that this is one of the times when an ‘improbable’ avalanche might actually occur.

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