Heading to Eastern Washington? Expect winter driving conditions in the passes.

Hey, football fans: Heading over to Pullman this weekend to watch the Apple Cup?

Planning to travel across the passes for some turkey with your relatives?

Thinking about hitting the slopes for opening weekend?

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Well, be prepared, because the weather may not be your friend if you’re heading over Snoqualmie and Stevens passes.

“It’s winter in the mountains, and people have not necessarily made that transition in their heads because it’s early in the season. People have a tendency to show up not prepared,” said Jeff Adamson, spokesman for the Washington State Department of Transportation (WSDOT).

While Adamson kept a close eye on Stevens Pass as skiers and snowboarders headed up Tuesday for opening day, his colleague Mike Westbay kept tabs on Snoqualmie Pass.

Westbay said this is the busiest weekend of the year on Snoqualmie Pass, with twice the number of travelers crossing it than on a typical weekend.

“Everyone should prepare for winter-driving conditions. Carry chains with them and know how to put them on. Allow lots of time to get where you’re going,” Westbay advised.

Expect rain and snow Wednesday night at the 3,000-foot level, which is near the base of the Summit at Snoqualmie, Westbay cautioned. The National Weather Service predicts 3 to 7 inches of accumulation Wednesday at higher Stevens Pass, with wind gusts to 25 mph.

The National Weather Service said motorists traveling over Snoqualmie and Stevens passes will see a break in the weather on Thanksgiving Day. Snow and rain will return on Friday with 3 to 5 inches of snow possible at Stevens, and snow will possibly return Saturday night.

WSDOT expects the heaviest snowfall on Sunday and Monday.

On White Pass, you can expect snow and winter conditions throughout most of the week, Westbay said.

Adamson said he doesn’t think traffic levels on Stevens Pass will reach the levels of a Fourth of July weekend, but the traffic will be boosted by a combination of skiers, holiday travelers and the fact the North Cascades Highway has closed.

The North Cascades Highway was temporarily closed on Monday afternoon because of concerns over snowslides and continuing heavy snowfall. The closure was made permanent for the season on Tuesday.

Like Westbay, Adamson urges travelers to be prepared for the worst. Travelers should be ready to spend time in their car, in winter conditions, if there’s a problem.

“Make sure you have water, food and medication,” he said. “We still have people who show up there in flip-flops and a T-shirt, so pack boots and a winter coat.”

Jennifer Sullivan: 206-464-8294 or jensullivan@seattletimes.com. On Twitter @SeattleSullivan.