Big snow expected in Cascades — and Seattle may get some, too

Driving over the mountain passes after Thanksgiving? Don’t wait too long to get moving.

The National Weather Service predicts Snoqualmie and Stevens passes will get 1 to 2 inches of snow Friday afternoon and evening. Heavier snowfall is on the way Saturday through Monday, when between 14 and 20 inches is expected at the two passes, said meteorologist Jacob DeFlitch.

In Seattle, most of that precipitation will fall as familiar rain. But between Sunday night and Monday, the city could get a rain-snow mix with little accumulation, especially in areas near Puget Sound, he said.

Meteorologists are watching a cold air system from British Columbia that could arrive midweek, potentially bringing another opportunity for lowland snow and a rain-snow mix.

“That’s kind of far out, and there’s a lot of uncertainty in the forecast,” DeFlitch said.

Regardless, it could be a good time to practice installing tire chains and review tips on driving in the snow.

The Washington State Department of Transportation sometimes issues notices that tire chains are required to drive through the mountain passes. In these cases, two-wheel drive vehicles must install chains. All-wheel and four-wheel drive vehicles under 10,000 pounds are not required to use chains, though WSDOT says all drivers must carry chains in case conditions worsen.

Snoqualmie Pass has closed twice this week after collisions occurred on snowy roads.

Some common-sense measures like clearing snow off your car before heading out, turning off cruise control, and keeping your distance from other vehicles can also help while driving in wintry conditions.

Before you hit the road, check the latest updates on the mountain passes and road conditions at wsdot.com/traffic.