Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

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

Multiple inches of water moving through the snowpack has set the stage for continued large or even very large natural avalanche activity. Avalanches originating at middle or upper elevations could run to valley flats, even at lower elevations. All varieties of unpredictable wet avalanches are on the table, including slabs, deeply entraining point releases, cornice fall, and glides.

Avalanche problems

  • Wet Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2–3

    Although the lower elevations are likely draining water, forming runnels, and healing, middle and upper elevations are still very much in transition - and that means that large to very large, destructive wet avalanches remain likely for these elevations. The rain to snow transition in most of this zone occurred on Sunday, and at upper elevations, that transition continues into Monday night. The result is that we're not very far past peak danger even by Tuesday.

    Wet avalanches that aren't the small wet loose variety are, by and large, highly unpredictable: You never know when they are going to release. Increased warmth on Tuesday continues to strain sagging cornices which may fail, triggering large and destructive avalanches on the slopes beneath them. Water continues to move along bedrock slopes, releasing glide avalanches without warning. Wet slabs will be the largest of them all and as all the recent rain moves deeper into the snowpack, it may pool and lubricate a crust, initiating the largest avalanches on Tuesday.

    Unfortunately, we don't have great travel advice to help you safely navigate terrain on or beneath slopes 35 and steeper. The risk remains too high for recommending travel on these slopes until we get a good overnight refreeze. Try to keep a buffer between yourself and slopes 35 degrees and steeper. If you choose to travel beneath large avalanche paths, travel through this area quickly. Very large avalanches could extend from steep upper or middle elevation start zones down into below-treeline areas, so make sure to recognize when you are in connected terrain.

     

    Example: Very large glide-initiated wet avalanche. One of the many wet varieties you might encounter on Tuesday.

    Photo: Eamon

Avalanche Discussion

Scattered natural D2 avalanches were reported from cornice fall triggers, glides, and wet slabs according to Mt Baker Pro Patrol. We expect that as temperatures continue to warm and more cold snow transitions deeper this activity will continue and could, in some cases, increase in size. These avalanche problems may not give you the feedback you normally see in the mountains and that's what makes these problems tricky. Safe travel is about maintaining a conservative mindset and reminding yourself that the rapid changes beneath the surface can still show up on the surface as an avalanche...and it will do so without warning.

Middle and upper elevations hung on to wet snow on Sunday, while only upper elevations remained wet snow on Monday. In the past 5 days, more than 5" of snow water equivalent has hit the Mt Baker area. More of this came in the frozen form at upper elevations, approximately equal amounts frozen and non-frozen at middle elevations, and the majority of this fell as rain at lower elevations. So, snowpacks will vary significantly in terms of water content and depth of water penetration by elevation. The transition should continue on Tuesday with even warmer weather along with sunshine. Keep in mind that the sun will melt a small amount of snow relative to the precipitation that just arrived, so it is not the sunshine driving the danger in this forecast.

The last couple of weeks have been riddled with human-triggered avalanches, partial burials, and a few unexpectedly more stable days that have for the most part, caught us by surprise. Some of the active days resulted in large (D2) avalanches being triggered, whereas at other times we predominantly had reports of several small (D1) avalanches. 

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