Conditions change quickly in the mountains. Chains may be required and pass closures are possible.
SEATTLE — With snowfall expected to continue through Saturday morning, conditions in the Cascade mountain passes could change rapidly.
Early Friday, Interstate 90 closed in both directions as was White Pass for avalanche assessment. U.S. 2 had closed earlier but reopened to traffic. Conditions are expected to vary throughout the day as snow continues to fall.
Before you head over the mountains, make sure to check pass conditions as closures are possible and vehicles may be required to chain up. Closures might also occur for avalanche control, as the risk of avalanches remains considerable to high through the Cascades, according to the Northwest Avalanche Center.
The Washington State Department of Transportation may close one direction or both directions of a pass if severe weather or collisions warrant a closure. Check if the passes are open or closed in each direction before you hit the road:
Closures for avalanche control allow specialized crews to remove the hazard by bringing down accumulated snow in a controlled fashion.
The Washington State Department of Transportation said they monitor about half a dozen chutes — areas free of trees where snow accumulates — at Snoqualmie Pass for potential avalanches.
Both Stevens and Snoqualmie have howitzers available for avalanche control. In clear weather, they can drop explosives from helicopters.
For the most part at Snoqualmie, bags of explosives are moved along wires called trams to the top of chutes, sometimes bags are dropped from ridges above.
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