Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

Mon
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Sunday should bring mellower and drier weather before another storm moves in. You can still trigger slab avalanches on steep, unsupported slopes, especially at upper elevations. Reduce uncertainty by choosing lower angle, more planar terrain. Monitor slopes overhead seeing direct sun in the morning.

Avalanche problems

  • Storm Slabs

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

    Slabs of wet sticky snow at mid-elevations should bond overnight. But with more new snow and colder temperatures at upper elevations, it would be wise to nibble at the edges of big terrain and assess instability instead of diving right in. As usual, you are more likely to trigger a larger avalanche on slopes with signs of recent wind transport.

    Track new snow depth and distribution as you gain elevation and change aspects. The firm 12/21 crust is found 2-3’ below the surface at mid-elevations. Measuring the depth above the crust is the easiest way to figure out how much more snow you are dealing with at upper elevations. Scoured snow surfaces, cornices, and drifts can show you the wind loading pattern in the terrain around you, but they may be partly obscured by snow that fell with less wind.

     

     

    Steep, convex rollovers like this are where you are more likely to trigger an avalanche in layers of new snow.

    Photo: Jason Speer

Avalanche Discussion

Southerly slopes could see a shot of sun in the morning around Hwy 542. The likelihood of seeing significant avalanche activity is low, but it's still a good idea to keep an eye on what's above you if the sun makes it out. Avoid traveling on or immediately below steep slopes where you see fresh rollerballs, new avalanches, or simply find wet, mushy snow.

Wet weather and wet snow were the theme for Saturday. Avalanche control work produced numerous but small slab avalanches in drier snow first thing in the morning. But a slight warm-up mushed out much of the snow at mid-elevations and limited avalanche activity to slow-moving, moist mank-alanches for the rest of the day. All reported avalanches were less than D2 in size. Low elevations saw rain or very wet snow.

The big question is what is going on higher in the mountains. Limited information has come from upper-elevation terrain due to continued storms and marginal visibility. It’s likely there is 4’ or more of new snow over the 12/21 crust. Colder alpine temperatures may have limited the kind of rapid bonding and settling of new snow layers we have seen at mid-elevations.  Bonding at the 12/21 crust might also be weaker at upper elevations.

It’s not a sure thing upper elevations will have greater danger. Given the uncertainty about recent weather and snowpack variables in the alpine, it would still be wise to make a thorough stability assessment if you get up high on Sunday.

 

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