Avalanche forecast

West Slopes Central

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
4 · High
Treeline
4 · High
Below
3 · Considerable
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Highlights

Avalanche danger will increase throughout the day as more snow falls, temperatures increase, and winds peak in the afternoon. Starting out, wind-drifted snow will avalanche with a human trigger, so avoid steep wind-drifted slopes. By midday, steer around large avalanche paths and lower-angle slopes beneath them. 

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1.5–2.5

    Early in the day, avalanches will likely be limited to human-triggered wind slabs. Avoid steep wind-loaded slopes. Expect danger to rise quickly as temperatures climb, snowfall continues, and winds increase to gale force. By midday and beyond, natural avalanches will become more likely. With rapidly increasing loading, avoid traveling beneath large avalanche paths.

    Avalanches may start out in shallower mid-storm layers, but as the day progresses, many could fail on the 3/8 crust buried beneath the snow that has fallen since Sunday. In the West Central zone, the 3/8 crust sits 1-3ft below the surface in non wind-affected areas. 

    Example photo: Large natural avalanches are likely on Wednesday. Avoid steep terrain and areas beneath avalache paths, where a slide could start, run, or stop. 

  • Loose Wet

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

    We don’t expect wet avalanche activity until around midday. After that, wet avalanches will begin creeping higher in elevation, possibly reaching mid-elevations by afternoon as rain and heavy, wet snow saturate the surface.

    At first, wet avalanches will probably require a trigger like a person on a slope, or by snow shedding from trees, cliffs, and steep rocky slopes. There could also be a mix of storm slab avalanches initiated by heavy, wet snow at the surface.

    Once the snow turns sticky and starts shedding naturally—likely around midday—it’s time to back off steep terrain. Move to lower-angle slopes and stay well clear of large slopes above you where snow could run down to you. 

    Example photo: Large, destructive wet loose avalanches could entrain a lot of snow, or trigger a slab avalanche on Wednesday. Avoid where these avalanches start, run and stop. Don't wait until they start running to do so- once snow gets sticky, that's a good enough indicator to avoid steep areas or runouts. 

Avalanche Discussion

At lower elevations, avalanches will likely be smaller and won't run as easily in areas with more broken bed surfaces since there was less old snow cover at these elevations. If there are areas with sufficient cover near the top of the lower elevation band, treat these areas similarly to higher elevations by steering around the bottom of large avalanche paths as well. 

Avalanches will be larger in areas that received more snow since Sunday over the 3/8 crust, like the Highway 2 corridor and the south side of the Mtn loop. As for the crust, in many steep areas it is already irregular after widespread rollerballs ran before it froze, so we're not quite sure how easily slides will run on the crust. 

We don't expect failures beneath the 3/8 crust, but if layers get wet enough that the crust is completely soft, although unlikely, there's a chance a large avalanche could trigger an even larger one on this layer. 

We're expecting up to six inches Tuesday night, and another 6-8" during the day- although some will fall as rain at mid and lower elevations. Winds will peak, reaching gale force, Wednesday afternoon. That night, we'll see the highest precipitation rates, although temperatures will cool. We expect natural avalanches to continue or peak Wednesday night. 

Regions covered