Seattle, Washington – Travel through Washington’s Cascade passes could become nearly impassable within hours as up to 12 inches of snow piles up by early Thursday, with the heaviest bursts targeting Stevens Pass before sunrise.
According to the National Weather Service in Seattle and Spokane, a Winter Weather Advisory remains in effect until 5 a.m. Thursday for the Cascades of Whatcom, Skagit, Snohomish, northern King, Chelan, and Okanogan counties. Snow totals between 8 and 12 inches are expected in higher elevations, with 4 to 8 inches above 4,000 feet farther east and gusts reaching 45 mph.
Stevens Pass stands out as a critical trouble spot, where a convergence zone developing Wednesday afternoon is expected to intensify snowfall rates and rapidly reduce visibility below 500 feet at times. Along U.S. Route 2, conditions may deteriorate quickly, with snow-covered pavement and spinout risks increasing overnight.
Communities including Mazama, Winthrop, Twisp, and Stehekin will also see accumulating snow, while lower elevations could pick up 1 to 3 inches. Blowing snow may create drifting across exposed roadways, especially near Loup Loup Pass.
Drivers should delay non-essential travel, carry tire chains, and prepare for sudden closures. Power outages remain possible where heavy snow weighs on lines. Advisories remain in effect through early Thursday, with additional updates likely if snowfall intensifies.
