Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

Wed
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

7:30 AM update: Increased danger to Considerable in below treeline, as water and snow amounts were slightly larger than expected overnight. Likelihood of you triggering an avalanche will increase as the day progresses and more snow continues to fall. The cooler temperatures accompanying this storm mean that snow could be deeper and lower density than a usual storm of this size, and avalanche problems could range from dry loose to storm slab to wind slab at higher elevations. Avoid steep slopes on Tuesday, especially as the snowfall continues to build later in the day. 

Avalanche problems

  • Storm Slabs

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

    You could trigger and get caught in a variety of storm snow avalanche problems during your outing on Tuesday.  We're not quite certain how this storm is going to play out, but we expect at least a foot of low density powder by the end of the day. Sunday we received about one foot, in some areas more, of low density snow, and on Monday we heard about wind loaded pockets and plenty of dry loose avalanches running with or without a human trigger. Some small storm slab avalanches released naturally.  Most of the avalanches were small. Some steeps just had low density powder, or "goose feathers" as one person called it, and the snowpack was relatively right side up with minimal slab development in some areas.

    Expect conditions to remain similar on Tuesday, but avalanches could grow in size and become more reactive as snow amounts increase. Wind slabs could develop more than they did on Monday, especially at higher elevations. Avalanches could fail within the new snow layer, they could fail on Monday's interface, or they could fail beneath Sunday's snow. This means an avalanche could easily be two feet or more in depth. There's a lot of uncertainty here, so be sure to stay on the conservative side during your travels. If you encounter any slablike qualities in the snow, steer around steep slopes. Slabs could be so soft that they may not be discernable from other snow in the vicinity. Don't ignore obvious clues like recent avalanches, whumphs, or long, shooting cracks.  If you have any doubts, steer clear of slopes steeper than 35 degrees.

    If you do get out on steep terrain, expect to trigger a dry loose avalanche at a minimum, so be prepared to manage sluffs on a slope and not get caught in one, as getting caught even in a small sluff could take you for a dangerous ride. 

    (12/19/2022) Although loose dry powder was reported in some nearby areas on Sunday, this wind loaded spot showed bullseye clues of long, shooting cracks, a good indicator to avoid nearby steep slopes.  Photo: Matt Lubar - Cascade Mountain Ascents

Avalanche Discussion

Well over 2 feet of newly fallen low density snow will exist by the end of the day Tuesday. Tree well, or SIS concerns are elevated in these circumstances, so travel with a buddy and be very careful around trees and other subtle openings in the snow that could swallow you.

A layer of surface hoar was buried Saturday night (12/18). Snow layers on both sides of the buried weak layer were soft in most cases, so we are uncertain how reactive avalanches could be on this layer. Keep in mind that as more snow falls avalanches might fail easier than expected on this buried weak layer.

If you get out on Tuesday let us know what you encounter by submitting an observation HERE.

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