Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

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

A storm just ended and an extreme warming period is about to start, without much of a break from avalanche activity. Some areas in the zone have a weak layer buried 3-4ft deep and you can trigger large, possibly unsurvivable avalanches on the layer at mid and upper elevations. Also beware of triggering avalanches in steep wind drifted features, and if you notice wet loose activity on sunny slopes, avoid steeper nearby terrain and areas beneath them as well. 

Avalanche problems

  • Persistent Slabs

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

    A weak layer of surface hoar beneath about 3-4ft of recent storm snow exists in the Baker backcountry area and has been found at Canyon Creek as well. Some areas in the zone may not have this layer. It is mainly present at mid and upper elevations, where it was not destroyed by either the sun or the wind, before getting buried on 3/9. 

    Avalanche activity has occurred on this layer since Monday, when several natural and human-triggered avalanches were reported, and spooked a lot of people. On Wednesday, skies cleared and we saw the results of several natural avalanches that likely failed on this layer in the Baker backcountry during the last of the storm on Tuesday, up to 4 feet deep. Avalanches broke in surprising ways and in unusual places. Some persistent slabs look like they were triggered by shallower slabs, which may continue to happen. 

    Fair weather on Wednesday led to the usual march to irresistible powder outside of Mt Baker Ski Area, and at least 3 large rider-triggered avalanches were reported. We are so glad that everyone escaped unscathed. Sledders at Canyon Creek also found unusual amounts of avalanche activity and remotely triggered avalanches during their day on Wednesday (OBSERVATION).  Human triggered avalanches are still likely on this layer on Thursday. If you choose to travel onto steep slopes in these areas you're taking a gamble as to whether you might trigger a large avalanche, which might be unsurvivable. 

    (3/13/2024)

    Large human triggered avalanches were reported in the Canyon Creek area on Wednesday. Some were remotely triggered, and deep enough to suggest they failed on the layer of buried surface hoar beneath the new storm layer. 

    Photo: Isaac Thistle

  • Wind Slabs

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

    You may find brand new or couple-day-old wind slabs during your outing on Thursday. Some slabs could be shallow, only a couple inches deep, whereas others may be a foot or two deep. If you see active signs of wind loading, which may be present along ridgelines at upper elevations, identify where snow is landing and avoid those areas. 

    Snow usually deposits below ridgelines, in gullies or around outcropping and features. Feel for stiffer slabs and search for textured, or rippled snow surfaces. The difference in heaviness may be subtle. You may see long shooting cracks. Steer around slopes greater than 35° where you identify wind loading, as you could trigger an avalanche resulting in a dangerous ride.

    (3/13/2024) If you zoom in you can see wind ripples coating most surfaces in the Baker backcountry. This is an indicator that wind affected most areas. Search for wind slabs during you outing!  Photo: Hilary Groh

  • Loose Wet

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

    Wet loose avalanche activity will pick up midday and you can expect slides to continue until the sun leaves a slope. Freezing levels transition from 3500ft in the morning to 8500ft at the end of the day and it'll be sunny. The sun will first moisten east-facing slopes a little in the morning, before shifting south and then on to west-facing terrain in the afternoon. As temperatures increase avalanche size will continue growing into the afternoon. 

    You may be able to start the day on sunny aspects, but plan on leaving them as the sun intensifies and wet loose avalanche activity begins. Small rollerballs will be your first indicators before small wet loose avalanches fan out. Slides may become large as the day progresses, digging deeper into all the low-density snow that just fell. When you notice any of this activity, transition to shady aspects or away from any slopes greater than 30° and the runout beneath those slopes as well. 

    Wet loose avalanches may trigger slab avalanches as they pick up mass while traveling down a slope. Make sure you plan your day so you won't have to exit through terrain that earlier did not have avalanche activity but by the end of the day, could be very scary and active.

    (1/27/2023)

    Mo

    Photo: Julz Holder - Grounding Truth

Avalanche Discussion

The storm wound down on Tuesday and totaled about 4 inches of water in the Baker backcountry, equating to about 4 feet of snow since 3/8. Other areas in the zone received closer to 3 inches of water, or 3 feet of snow. Storm slab avalanches midway through the new layer ran during and just after the storm, and persistent slab avalanche activity from beneath the storm snow was notable in the Baker backcountry. 

The Cascades are heading into a stretch of very warm sunny weather. It will be the first big, spring-like warming event of the year, with high temperatures in the 50’s and freezing levels over 10,000’. Very warm conditions through the weekend could produce significant slab and loose snow avalanches.  As with any warming event, there is a high level of uncertainty as to where, when, or even if this scale of avalanche activity will occur. On the other hand, big natural avalanches aren’t really the kinds of things that should be taken lightly. It’s worth noting that smaller wet loose or wind slab avalanches, cornice falls, or snow shedding from cliffs can provide the trigger needed to pull out a very large avalanche. When planning for the weekend, consider that this is one of the times when an ‘improbable’ avalanche might actually occur.

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