Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate
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Out of date — this forecast expired 5 months ago. You’re viewing past conditions, not the current bulletin.

Highlights

High snowfall rates will create reactive slabs that you can trigger on any aspect. Evaluate mid-storm layers and the bond to the new crust before engaging with steep open slopes of consequence. Slabs could be large, widely propagating, and difficult to escape at the highest elevations. 

Avalanche problems

  • Storm Slabs

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

    High snowfall rates Tuesday night and at times on Wednesday will combine with lower snow levels to form a reactive and potentially widespread slab that increases in depth throughout the day. Winds actively redistributing the fresh snowfall will load  lee slopes, enhancing the avalanche concern in typical start zones. Up to 6000 to perhaps as high as 7000 ft, a thick layer of saturated snow will be slowly refreezing from the top down by Wednesday. The new snow is likely to be well bonded to the underlying crust, but this is worth verifying with a stomp on a small test slope. While you're at it, look for potential mid-storm instabilities created by high snowfall rates or graupel layers. Hand shears can also give you a sense for how the storm layer is evolving as you move through time and terrain. When in doubt, steer around rollovers and slopes steeper than 35 degrees.

    Above Tuesday's rain/snow line, 2.5" of water equivalent arriving Tuesday through Wednesday is likely to arrive as snow, perhaps up to several feet. On shaded aspects, this snow overlies a thin layer of faceted snow above the 3/21 crust. Avalanches at this elevation could be large and break widely across terrain features. Once you lose the wet layer of snow under the refreezing crust as you ascend, avoid all steep, open slopes.

    Example: Evaluating a small poorly supported "test slope" with a hard ski cut to see if there were any instabilities in the new storm layer.

    Photo: Irene Henninger

  • Glide Cracks

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

    Temperatures should be much cooler and rain a distant memory by Wedneday, but water over 1.5" of liquid water is still draining the snowpack in many middle and lower elevation locations. As this water works its way along the base of the snowpack and over steep, slick rock or grassy slopes, it lubricates the entire snowpack enough to initiate climax "glide" avalanches. Glides were active in our recent atmospheric river just last week, so the cracks and brown frowns formed in the snowpack may wake back up quickly. If you see signs of brown frowns or areas of snow peeling off steep slopes, give these areas of unstable snow a wide margin for safety on the slopes below. With some good fortune and strong cooling, this probablem becomes less likely to materialize once strong, supportive crusts form underneath the new snow.

    (3/19/2026)

    Glide cracks starting to form in the usual spots in the Baker backcountry, on the east face of Herman. 

    Photo: Zack McGill - Cascade Mtn Ascents

Avalanche Discussion

The location of an intense band of convergence Tuesday night and at times on Wednesday will play a significant role in the development of storm slabs and associated avalanche danger. Areas where the convergence sets up for several hours or more are likely to have the kind of high snowfall rates that drives storm slab hazard. Even if the higher snowfall rates ease, additional snow might not allow these storm layers time to settle. Moderate SW and SSW ridgeline winds are also a factor over the next 24 hours. These come on the back of extreme winds which closed the Mt Baker ski area by mid-day on Wednesday. Winds at Pan Dome were sustained in the 40-50 mph range with gusts just shy of hurricane force (75 mph). The winds were accompanied by heavy snowfall early in the day that brought 2-3" of dense snow and formed stubborn drifts at middle elevations up to 8-12" deep. Snow changed to rain in the late morning hours and saturated the new snow along with the weaker faceted snow underneth, at least at middle elevations. 

1.76" of water equivalent was recorded at Heather Meadows from early Tuesday through 6PM. Much of this precipitation arrived as rain at middle elevations. The rain-snow line reached an uncertain elevation on Tuesday, likely in the 6000-7000 ft range, before snow levels dropped late in the day and rain turned to graupel at the ski area base shortly after 5 PM. There could be massive drifts at the highest NWAC forecast elevations that still need time to settle undernearth colder lower-density surface snow by Wednesday. These elevations might have a similar snowpack setup might to the East North zone. The East North experienced widespread, reactive slabs and high snowfall rates rather than a changeover to rainfall on Wednesday. The slabs in the West North would likely be deeper and even more consequential. Give all the recent high elevation snow more time to settle before getting onto larger terrain features at the highest elevations.

See the gallery below for a sampling of conditions prior to the ongoing storm.

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