Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Snow totals could be around half a foot overnight Tuesday, plus wind, so expect to find small to medium-sized wind-drifted slabs that you could trigger an avalanche on. Search for stiffer, smooth or textured snow and avoid these deposits on steep slopes, especially where terrain traps exist below. Increasing daytime temperatures may result in small wet avalanches at lower elevations, but if the sun pops out, steep slopes facing the sun at higher elevations may have small avalanches in the new snow as well. 

Avalanche problems

  • Wind Slabs

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

    We may not see a huge storm Tuesday night, but we're getting enough snow with wind-effect to increase the avalanche danger to Moderate. It's been a week since any dry snow avalanche problems were in the forecast, so it's time to shift your brain back to thinking about dry snow. Drifts may grow to 1ft or deeper, and it's possible these drifts could react to a human trigger. As the day progresses and warms, it may become harder to trigger wind slab avalanches. 

    Avalanche activity will remain limited to the new snow layer over the old, previously wet snow. At lower elevations, we expect that the new snow may bond better to the underlying, previously wet surface, but as you travel higher drifts may not be bonded as well. The new layer should be shallow enough that you can do simple hand tests to see how well the wind-drifted snow sticks to the underlying layer. 

    Feel for thicker, stiffer, or hollow-seeming snow beneath you. Scan nearby surfaces for smooth, drifted "pillows", or textured expanses. You're most likely to find deposits on rollovers, around rocky outcroppings, and in gullies.  Use small test slopes to see how drifts behave. If you identify any of these wind slab characteristics on slopes greater than 35°, steer around them. 

    (2/19/2025)

    Example photo: Use small test slopes with wind-affected snow like this one to see if they react to a human trigger. Test slopes aren't always reliable, so even if you aren't getting results here it doesn't mean it's open season on larger slopes. 

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    As temperatures increase and if snow gets sticky and moist, small, wet loose avalanches could run naturally or with a human trigger in the new snow layer. If the sun pops out, there may be a quick onset of rollerballs and subsequent small avalanches in the new snow layer on steep slopes facing the sun. 

    We expect any wet avalanches, if they occur, to remain small. If snow starts getting moist and sticky or you begin to see rollerballs or small wet avalanches, shift to lower-angle terrain away from steep slopes or move to shadier aspects. 

    (12/10/2024) Example photo: Rollerballs and small wet loose avalanches like the ones that might occur on Wednesday.  Photo: Julz Holder - Grounding Truth

Avalanche Discussion

Even avalanches that may not be large enough to bury you could still kill you if you're caught in one or knocked over while you're above a terrain trap. Stop and reevaluate the snow before entering an area where you're above an abrupt bench or gully, over a cliff band, or patch of trees or rocks.

An atmospheric river bringing rain to upper elevations produced many large and very large wet avalanches February 21-23, some of which stepped down to our January Drought Layer 3-5ft beneath the surface. The storm concluded on the 25th with 1-2ft of dry snow and subsequent small to large storm slab avalanches. The storm totaled about 7 inches of water. By February 26, temperatures increased, and wet avalanches overwhelmed our forecasts for the next five days.

We're finally seeing at least a brief cooling trend where old snow layers should firm up a bit, and lingering glide, cornice, or random snow block fails are now unlikely. In areas where the wind stripped the new snow away, you'll probably find crusty and irregular surfaces. In wind-sheltered spots, we expect that the new snow layer fell right side up with temperatures cooling during the snow event, so we don't expect much avalanche activity in those areas. 

If you make it into the backcountry please share with us what you find by submitting an observation HERE or on the Avy app. 

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