Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

Sun
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

A shift to warmer, sunnier weather will bring a change in avalanche problems. Avoid travel on or directly under steep slopes where you see rollerballs, small wet avalanches, or snow becoming wet and mushy. A weaker snowpack may exist in or near North Cascades National Park. Read the forecast for East North if you’re heading that direction.

Avalanche problems

  • Storm Slabs

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

    New snow amounts continue to vary widely across West North. Some areas have picked up only a few inches over the past few days, while others—like the Baker Backcountry and Schriebers—have seen close to a few feet. As usual, expect slab size and reactivity to hinge largely on how much recent wind loading a slope has received. Still, assess how much new snow you’re dealing with and how well it’s bonded before committing to steeper terrain, whether sheltered or wind-loaded.

    Track new snow depth and stiffness as you gain elevation and move between aspects, and use small test slopes to gauge bonding. Recent natural and human-triggered slabs were more common on southerly aspects, where slabs formed over crust and were reportedly less reactive where soft snow remained beneath the slab. Slabs may also become more reactive when they get their first hit of sun.

    (1/29/2021) 

    Sun and warming can wake up slab instabilities - at least before they turn the snow to mush.

     Photo: Pete Durr

  • Loose Wet

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

    Wet loose avalanches will be possible if new snow reacts to the sun and warmer temperatures. Avalanche size will vary with how much recent snow has accumulated—expect larger, more consequential slides in areas that picked up the most new snow. Size also depends on terrain, as steep, sustained fall-line slopes can produce more powerful avalanches. But even a small wet loose avalanche can pose a serious risk if it carries you over a cliff, into a creek, or through rocks or trees. Keep track of sunny slopes overhead as the day warms.

    (3/17/2023)

    Wet loose avalanches frequently start when snow sheds off of rocks and onto the slope below.

Avalanche Discussion

Avalanche forecasts for large zones are often difficult to pin to a single danger rating, and Saturday may be especially challenging given the wide variation in new snow amounts, the potential for both slab and loose avalanches, and the uncertain distribution of persistent weak layers. Be prepared to find danger a full step higher or lower depending on where you travel within West North. Build flexibility into your plan so you can adjust based on what you find.

It was the second day in a row that precipitation and snowfall amounts exceeded the forecast in the Baker Backcountry. Observers found about a foot of new snow, along with a handful of small natural avalanches and one large slab released during control work. In general, the new snow is settling and bonding, but instability remains—especially just above a crust 12–16 inches down on south aspects. With lingering uncertainty, choose lines with minimal consequences if your slope-scale stability assessment turns out to be wrong. Or simply stick to slightly lower-angle terrain.

Persistent weak layers are a concern in zones surrounding West North, and buried facets or surface hoar may still exist beneath recent storm snow. Earlier this week, some natural, explosive, and human-triggered avalanches failed at a layer of persistent grains.

In West North, however, avalanche activity has been limited and sporadic. Red flags like whumphing and shooting cracks have not been widespread, and persistent weak layers have been harder to find—though not impossible. We’re not calling it a clear persistent slab problem, but you could still encounter one in less-traveled areas with fewer observations.

Regions covered