Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

If you hit the right spot on a big, steep slope you could trigger a large avalanche that could be unsurvivable. Weak layers under the 3 or so feet of new snow are inconsistent and it's hard to tell where they may exist, so avoid large steep slopes to guarantee you don't trigger one of these large avalanches. You may find wind-drifted slabs on exposed slopes at any elevation, so avoid thicker wind deposits of snow in steep areas. 

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–2.5

    Large and unusual avalanches, signs of instability, and a poor snowpack structure are all indicators of a persistent slab avalanche problem. Weak upper layers developed during the January drought and are now coated with 2-4 feet of snow. The snowpack has had a couple days to adjust since the storm ended, when we saw multiple human-triggered and natural avalanches, and now it's just waiting for the added weight of a human to stress the weak layer enough to avalanche. 

    It's hard to identify where exactly you might find this weakness, due to the unusual patchwork of layers that formed during the January drought. Structures vary across the zone, and even across the same slope. Big triggers like a snowmobile or group of people could trigger an avalanche where the weight of a single person might not. If you do trigger an avalanche, it could propagate widely, release in adjacent terrain, from the middle, or maybe even from below a slope.

    Don't ignore signs of instability. But, don't expect to experience any signs of instability before you trigger one of these avalanches- the usual indicators like whumphing or shooting cracks may not happen. Snow pits likely don't paint the whole picture, as the weakness is very inconsistent even on a small scale. 

    You might be able to get away with stepping out onto steep slopes without result, but maybe the next slope over is where you might trigger an avalanche that could kill you. It's hard to tell exactly where an avalanche could happen. If you don't want to risk being caught in one of these avalanches, avoid traveling on large, steep slopes. If in doubt, avoid terrain beneath large steep slopes as well. 

     

    (2/3/2025)

     Avalanche control work on Monday morning produced this large slab avalanche.  The crown was estimated to be around 4' deep. It likely failed at the old-new interface or in weak snow, faceted snow below it. 

    (SS-AL-D2-O)

    Photo: Mount Baker Ski Area

  • Wind Slabs

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

    You may be able to trigger an avalanche on recently wind-drifted snow. Low-density snow doesn't require much wind to redistribute, and the slabs could be very soft. Even if you trigger a smaller avalanche that doesn't seem like a big deal, it may be the additional weight needed to overload the underlying weak layer and produce a larger avalanche. 

    Wind will probably be light, but search for actively blowing snow and identify where it lands. Textured or scoured snow surfaces and cornices will point towards slopes holding freshly drifted snow. You might be avoiding big, steep open slopes due to danger from larger avalanches, but smaller terrain could have a wind slabs ripe for you to trigger an avalanche on as well. 

    (12/26/2024)

    Example photo: Wind rippled snow surfaces at about 4500' indicating these slopes may be easier to trigger an avalanche on. 

    Photo: Irene Henninger

Avalanche Discussion

Many riders were out on the Arm, backcountry adjacent to Mt Baker Ski Area on Tuesday - the first nice day since the storm ended. No one triggered an avalanche, but despite all these slope testers, we aren't confident that there isn't an avalanche problem out there. Don't be lulled into a false sense of security because there are probably still places where you can trigger a large avalanche on these underlying weak layers, it just hasn't been found yet.

Most of the persistent slab avalanches occurred on north-facing aspects, which is probably where you're most likely to encounter the persistent problem. There may be a tiny slice of steep south-facing terrain that has a solid melt-freeze crust at the old snow surface that would limit underlying avalanches, but finding those spots would require quite a bit of precision, and the weakest snow may exist just adjacent to those crusts. 

If you decide to step out into steeper terrain, increase your survival chances by having a partner, only exposing one person at a time to the slope, and be equipped with a transceiver, shovel and probe. Know how to use your rescue gear and practice regularly so that you can quickly dig your friend out before they die of asphyxia if they didn't die from trauma first. 

 

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