Avalanche forecast

West Slopes Central

Northwest Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 3 years ago.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

Highlights

A wind shift to the east will bring cooler temperatures and stronger winds. Look for and navigate around steep slopes where wind-drifted snow is accumulating.

Avalanche problems

  • Wind Slabs

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

    Wind speed and the amount of loose snow available for transport will likely be the two variables that determine avalanche danger. Locations farther east in the zone - or near major mountain valleys - should see stronger winds. But sun crust could hold in place loose snow that might otherwise drift and make a wind slab downwind.  Use your own observations to figure out where you are more or less likely to trigger a wind slab.

    Active loading will occur in locations that experience higher wind speeds. Use standard clues like cornices and wind-scoured surfaces to help identify the local loading pattern if the wind isn't blowing. Hand shears and test slopes on small, wind-drifted features can give you a sense of slab reactivity. Don't linger where you observe wind loading in the terrain above. You might see a few natural avalanches in places with the most wind transport. 

    Example of wind scouring snow from ridgetop and transporting it onto leeward slopes below.

Avalanche Discussion

Avalanche danger will mostly be confined to wind-loaded terrain. The only exception is where lingering weak layers are still in play. Observers at mid-elevations have found that the storm layers are generally bonding well, and faceted snow below the new snow doesn’t seem to be an issue. But small natural and human triggered slab avalanches were reported from upper elevations on Monday. Areas that experienced cooler temperatures and/or less wind during the last storm might have slightly weaker layering.   

No observations were submitted by Tuesday afternoon to say either way if wet avalanches came to fruition in the forecast zone. There was more sun than the previous day, but temperatures were slightly cooler, and north and east winds were stronger. The sun's warmth might not have been enough to win out over the temperatures and wind - especially where a thick sun crust protected drier snow below.  

There is a good chance the peak of wet avalanche activity occurred Monday when the fresh snow got its first shot of sun. The other possibility is local variations in sun, wind, and temperature produced differences in avalanche activity in different areas on different days. Yet another example of how avalanche forecasts are general summaries of conditions you might see - as opposed to exactly what you will see - on any given day in the mountains.

 

 

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