Lawinenlagebericht

West Slopes Central

Northwest Avalanche Center
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Lawinengefahr

Tue
Hochgebirge
3 · Erheblich
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Kernpunkte

We have several feet of new snow and the surface layers are very light and fluffy. You can trigger avalanches that might be around a foot deep, or possibly deeper, in the surface layers, mainly in wind affected areas but possibly other non wind-affected slopes as well, so avoid travel in steep areas. Deep, unconsolidated snow, tree wells and other mysterious holes in the snow may be the most dangerous part of your outing on Monday. 

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1–2

    On Sunday our neighbors to the north in the West North zone reported several mainly small natural and human triggered avalanches. Some were wind slabs and some were storm slabs. In the neighboring Stevens Pass and Snoqualmie zones, minimal new, shallow slab avalanche activity was reported. Depending on where you are in the zone conditions may favor one nearby zone versus another. 

    About half an inch of water is forecasted to fall between Sunday night and the end of the day Monday. This snow will add to the already voluminous amounts of light, dry snow we have at the surface of the snowpack. Due to the cold temperatures, the snowfall amount may end up being close to a foot.  Very unusual slab/loose avalanches may run in this snow. Avalanches will probably mainly be small, but some large avalanches may occur.

    Avoid slopes steeper than 35° on Monday. If you see natural avalanches running, avoid terrain beneath steep slopes as well.

    (3/3/2024)

    A small wind slab pocket, 3-6" deep, naturally failed in the neighboring West North zone on Sunday. 

    Photo: Zack McGill - Cascade Mtn Ascents

  • Loose Dry

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–1.5

    Cold, light snow at the surface is easy to push around and get moving in steep terrain. While mostly small, loose snow avalanches can pick you up and carry you downhill into a tree, gully, or other hazards. Be aware of how much snow is moving with you if you enter any steep terrain. Loose avalanche may behave unusually in this deep, light layer of snow, they may start as loose but then might trigger a slab avalanche further down. 

    The sun hasn’t had much of an effect the last few days, but when it does eventually come out for real and warm up the snow surface, be ready for a round of loose snow avalanches. Look for rollerballs and small loose snow avalanches if the sun makes and appearance. Warming can also form a reactive slab from loose dry snow at the surface.

    (2/22/2023)

    An example photo of small dry loose avalanches, or sluffs. 

    Photo: Katie Warren

Avalanche Discussion

The setup for deep snow immersion or disappearing into a tree well is currently about as dangerous as it gets.  Many feet of light and unconsolidated snow combined with previously low snow cover have created countless traps that seem fully covered at the surface.  Avoid traveling close to trees, have a partner, and keep them in sight at all times.  A tree well was responsible for a fatal accident in backcountry terrain on Friday.

The last storm left behind deep crowns and debris from natural avalanches in neighboring zones. Layers of weak faceted snow that failed under extreme loading during the latest storm are the likely culprit. Avalanche forecast zones to the south (West South), the entire east slopes of the Cascades, and also to the north (Canada) have legitimate persistent slab problems with continued avalanche activity related to similar layering.

Now buried under several feet of new snow, it’s unlikely - but not impossible - a person could trigger a deeper avalanche. The best chance would be on northerly aspects at upper elevations, and where the snowpack is also shallower over the Early February Crust. Locations farther east in the zone may have a better-developed weak layer and less snow over the crust. 

Don’t ignore signs of instability like whumping or shooting cracks - they are the best sign that you could trigger one of these in steep terrain. Bigger loads like a falling cornice, smaller avalanches or group of people might trigger one of these larger avalanches where a single person would not.

Your avalanche, snowpack, or weather observations are extremely valuable to the avalanche community. Help create a more accurate avalanche forecast by submitting your observations here. 

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