Avalanche forecast

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Northwest Avalanche Center
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Avalanche danger

Fri
Alpine
4 · High
Treeline
4 · High
Below
4 · High
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Highlights

You should avoid traveling in and around any avalanche terrain on Thursday. A powerful winter storm will create very dangerous avalanche conditions. Heavy snow and warming temperatures will initiate a widespread natural avalanche cycle, and avalanches may occur in unusual locations.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Certain
    Size
    2–3

    Heavy snowfall with warming temperatures and a weaker than average Pacific Northwest snowpack set us up for a very widespread avalanche cycle. Large natural storm slab avalanches will occur at all elevations, and some may be large enough to run through lower elevation bands. There is potential for these avalanches to run on crusts and weak layers deeply buried in the snowpack. Avalanches may run to the ground in locations further east in the zone where snowpack depths are lower.

    Areas east of the Cascade crest may see unusually high snow accumulations, where up to 3 inches of precipitation is forecasted to fall as snow. Areas closer to the crest may pick up nearly 5 inches of precipitation as snow. With this much new snow, even avalanches within the storm snow could be very large. Thursday is a good day to avoid the mountains altogether. 

    (1/4/2022)

    Expect storm slabs like these to be widespread and larger in many areas on Thursday. 

    Photo: Dallas Glass

Avalanche Discussion

Precipitation rates will peak overnight on Wednesday, followed by warming temperatures on Thursday morning and increasing winds. This rapidly changing weather will create a mixed bag of unstable snow, all of which will likely produce avalanches large enough to bury or kill you. Precipitation types are hard to determine with this warm air overriding cold air pooled east of the Cascades. There is a chance of mixed precipitation and ice accumulation, creating a different but significant hazard for travel. And if warm air erodes the cold air pooled east of the Cascades, a change to rain may occur and create the potential for wet avalanches. 

While most observations have indicated a good bond between the upper snowpack and the Solstice crust, now buried 2-3 feet below the surface, some surprising avalanches in other zones have occurred on this layer. Including an explosive triggered slab that stepped down to this layer during avalanche mitigation work at Mission Ridge on Monday. These layers will be the likely culprits to any very large avalanches on Thursday.

 

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