Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

Sat
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Wet avalanches are our largest concerns, but they're fairly predictable: once the sun's been on a slope for a short time and the snow starts to moisten or slide, get off that slope and the terrain beneath it. A weak layer of snow is buried 3-5ft deep on northerly slopes at mid and upper elevations, and people easily triggered avalanches on it at Excelsior on Wednesday. It's also been found in the Baker backcountry, but doesn't appear as active at Bearpaw and Schreibers. 

Avalanche problems

  • Loose Wet

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

    Friday is the first official day of us really cooking. Freezing levels will transition from an unseasonable 10,000ft to 11,000ft during the day. Wet loose avalanche activity will start quickly as sun touches slopes, and you can expect slides to continue until the sun leaves a slope. The sun will first wet east-facing slopes in the morning, before shifting south and then on to west-facing terrain in the afternoon. Avalanche size will likely grow all day. A crust exists on most of these slopes from Thursday, but it probably won't take long for the sun to cook through that crust. 

    You may be able to travel really early on sunny aspects, but beware, as conditions can change very quickly. Small amounts of avalanche activity, or rollerballs, will be your first indicators before wet loose avalanches increase in size, probably becoming large and destructive. Slides will dig 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.

    (3/14/2024) Large D2 wet loose avalanches on Thursday in the Baker backcountry. E, 4500ft. 

  • Persistent Slabs

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

    A weak layer of surface hoar buried beneath about 3-5ft of recent storm snow has failed in avalanches in the Baker backcountry, and in several remotely triggered avalanches in Excelsior on Wednesday. It doesn't appear to remain a problem at Bearpaw or Schreibers, but the jury is still out on other areas in the zone where it may be present. It mainly exists 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 many people in the Baker backcountry. On Wednesday, skies cleared and we saw the results of several natural avalanches that likely failed on this layer 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 avalanches, which may continue to happen. 

    An explosive triggered avalanche outside Mt Baker Ski Area on Thursday morning produced a very large avalanche, spanning 300ft wide and 5ft deep, likely failing on this buried surface hoar layer. On Wednesday, sledders at Excelsior remotely triggered several large avalanches,(OBSERVATION), yet folks at Bearpaw didn't trigger any avalanches- which doesn't mean it's not there, but possibly harder to find.  No new avalanches were found on this layer at Schreibers either, despite plenty of slope testing. Nevertheless, expect that you can trigger an avalanche on this layer. If you choose to travel onto steep slopes in areas where it might be found you're taking a gamble as to whether you might trigger a large avalanche, which might be unsurvivable. 

    (3/13/2024)

     A very large snowmobile triggered  avalanche in the Excelsior area. E, 5500'. SS -AM - R2-D2.5 - I 

    Photo: Isaac Thistle

  • Wind Slabs

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

    Folks out on Thursday reported wind slabs are becoming more difficult to trigger. They may be trending towards unlikely, but we have enough uncertainty that you shouldn't discount new or few-day old slabs completely. Some slabs could be shallow, only a couple inches deep, whereas others may be a foot or two deep. 

    Snow usually deposits below ridgelines, in gullies or around outcropping, features, and steep rollovers. Feel for stiffer slabs and search for textured, or rippled snow surfaces. The difference in heaviness may be subtle. Your weight on a wind slab may cause 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) Wind ripples coating most surfaces in the Baker backcountry. This is an indicator that wind affected most areas. Search for wind slabs during your outing! Photo: Hilary Groh

Avalanche Discussion

Conditions are weird out there right now. We went from a February snowpack of a meager few feet of mainly icy snow, then more than doubled the snowpack within a few weeks. There's still strange gaps and unusual features in the snow, and now we've got this rapid warming affecting the several feet of low-density snow we've just received. With such rapid changes make sure to have a healthy respect for your surroundings. 

The storm finished 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 the layer of buried surface hoar just beneath the storm snow was noted in some locations but not others. 

The Cascades are feeling the brunt of 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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