Avalanche forecast

West Slopes Central

Northwest Avalanche Center
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Avalanche danger

Tue
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

An uncertain weather forecast requires that you assess avalanche conditions in the area you travel - you may find more or less wind and snow than expected. You can reduce uncertainty by limiting your exposure to avalanche terrain, especially during stormy conditions that make travel and observations more difficult. 

Avalanche problems

  • Wind Slabs

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

    Start out the day with a conservative mindset and stick with lower-angle, wind sheltered terrain to reduce risk. Identify and avoid steep slopes that hold fresh wind slab. Natural avalanches could occur during periods of heavy snowfall and higher wind speeds. 

    If traveling near or above treeline you won’t need many clues to figure out where winds slabs are forming - wind blown snow will probably just point the way. You can also monitor changes in snow depth and stiffness as you gain elevation or change aspects to hunt down fresh wind slab. Scoured or eroded snow surfaces can help as well. 

    Strong winds forecast for Monday will build yet another round of slabs. New snow from the past few days will be the raw material. The size and extent of new wind slabs will depend on a combination of how much new snow is on the ground versus wind speed. Less snow and lighter wind? Less wind transport and therefore less wind slab. If you see the opposite? Expect more of everything.

     

    (12/31/2022)

    An example of a human-triggered avalanche in steep and convex wind loaded terrain. 

    Photo: Adam Ü

Avalanche Discussion

The current weather pattern is tricky to forecast so you may find avalanche conditions more or less hazardous than expected. Subtle changes in wind, precipitation, and temperature can have big impacts on how the day pans out. These variables affect avalanche reactivity (how easy to trigger), distribution (everywhere or just in a few places), and size. Be prepared to make and act on your own observations on Monday.

Lower snow levels and yet another fast moving storm put down 4" by late-afternoon Sunday. To the north of West Central, heavy snowfall and strengthening winds began to build small, reactive wind lips and slabs in exposed areas. Some test features even produced shooting cracks by the end of the day. The new snow did much to improve riding conditions. Less new snow was seen in Snoqualmie and Stevens Pass.

A few more small glide avalanches were observed, mostly slabs sliding off steep, wet rock faces. Though not a widespread hazard, glide avalanches, cornices and other wet avalanche types present some risk until temperatures drop and stay below freezing. Take note of what is overhead, especially if snow changes to rain or there is a sudden increase in temperature. 

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