Heavy Rain and Snow Threaten the Pacific Northwest With Intense Weather During Thanksgiving

• Heavy rain and snow could cause travel delays during Thanksgiving
• Weather affects mountain passes
• Affects key travel routes

A powerful atmospheric river will bring torrential rain and mountain snow to the Pacific Northwest this week, complicating Thanksgiving travel during one of the busiest travel periods of the year.

AccuWeather meteorologists warn that the phenomenon could persist through the holiday itself.

Rainfall was already recorded Sunday in Washington and Oregon, though a brief break is expected between Monday and Tuesday.

Beginning Tuesday night, a new surge of moisture will intensify rainfall.

Rain That Could Trigger Flooding and Travel Delays During Thanksgiving

Dan Pydynowski, senior meteorologist at AccuWeather, warned that the heaviest rain will directly impact Interstate 5. This key corridor between Seattle, Olympia, and Portland could face major delays just before the holiday.

Tuesday through Thursday is expected to be the most active period of the atmospheric river, with the heaviest rainfall likely on Wednesday — traditionally the busiest road travel day of the year.

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Authorities anticipate 1 to 4 inches (2.5 to 10 cm) of rain across western Washington and northwest Oregon. Higher elevations could see increased totals, causing rising creeks and hazardous street flooding.

In addition to rain, wind gusts over 40 mph (64 km/h) could affect coastal areas. These winds may cause minor damage and further create Thanksgiving travel delays.

Snow to Complicate Mountain Pass Travel

Rain will not be the only challenge for Thanksgiving travelers — snow will play a significant role in mountain passes, especially in Washington.

While Oregon’s Cascades should see mostly rain at lower elevations, Washington faces a different scenario. Pydynowski cautioned that Stevens Pass, at a higher elevation than Snoqualmie Pass, could receive snow mixed with rain.

This mix may leave several inches of slushy accumulation on the roadway, reducing vehicle traction. U.S. Route 2, which crosses Stevens Pass, could experience significant delays.

In higher elevations such as Mount Rainier, fully wintry conditions are expected. The volcano may receive several feet of snow accompanied by strong winds and reduced visibility — a hallmark hazard of this Pacific Northwest storm.

Conditions to Improve by Black Friday

Despite expected impacts from Tuesday through Thursday, the weather is forecast to stabilize toward the end of the week. Meteorologists say rain and snow will continue through Thanksgiving Day.

Afterward, a drier air mass will arrive just in time for Black Friday shopping. This break will offer better conditions for those unable to travel before the holiday.

Even so, authorities urge caution on the roads throughout the week. Travelers should monitor local weather alerts and anticipate delays caused by flooding or snow.

The atmospheric river will leave a significant mark on the Pacific Northwest, and residents should prepare for days of rain, wind, and possible travel disruptions on key routes, AccuWeather noted — clear indicators of a severe Pacific Northwest storm.