An intense atmospheric river has bombarded the Pacific Northwest with heavy precipitation since Thursday, causing serious inland and coastal flooding in Washington state.
The intense jet of moisture has produced record-setting rainfall, high seas and, in the mountains, copious snowfall.
On Friday morning, the most severe flooding was concentrated near Chehalis, Wash., about 70 miles south of Seattle, where high water left people stranded and standing on vehicles. They were later rescued by boat.
High water closed Interstate 5, which connects Seattle and Chehalis, for a 20-mile stretch for three hours (it has since reopened) while members of the Washington National Guard were deployed to help residents coping with flooding.
“The Newaukum [river] near Chehalis and the Skookumchuck near Bucoda are both over major flood stage,” the National Weather Service forecast office in Seattle wrote in a discussion Friday, adding that major flooding was also possible downstream.
Advertisement
The Weather Service said 24-hour rainfall totals in this area had swelled to 3.5 to 6 inches. In nearby Hoquiam, about 45 miles to the west, 5.78 inches fell Thursday, its wettest day on record.
Lewis County - WSP Pilots took some great aerial shots of the area. #1- NB I5 Backup #2-Chehalis Airport #3-SR 6 Near Adna #4-SR 6 Littell pic.twitter.com/UqtGeEvtKS
— Trooper Will Finn (@wspd5pio) January 7, 2022In Seattle, two inches of rain fell Thursday, a record for Jan. 6.
Flooding affected large areas of western Washington, especially near rivers. Major river flooding was affecting Lewis (where Chehalis is located), Thurston and Mason counties, the Weather Service said, with minor flooding in Pierce, King, Snohomish and Grays Harbor counties.
Excessive precipitation also walloped the mountains. Five to seven inches of rain soaked the lower elevations of the Cascades, the Weather Service reported, while multiple feet of snow socked the high elevations.
On Thursday, heavy snow, low visibility and avalanche concerns forced the closure of Interstate 90 over Snoqualmie Pass, the major route across the Cascades. The National Avalanche Center rated the danger as a level 4 out of 5. “You should avoid traveling in and around any avalanche terrain as a powerful winter storm will create very dangerous avalanche conditions,” the Center wrote.
This is what our crews are dealing with on Snoqualmie and White passes - large snow drifts, avalanche danger, falling trees, and large amounts of snow on signs. It's too dangerous for crews to go in and assess and another round of snow is expected in the next 24 hours. pic.twitter.com/ISHxowH856
— Snoqualmie Pass (@SnoqualmiePass) January 6, 2022To the west, major shoreline flooding slammed coastal Whatcom County, prompting a coastal flood warning through 2 p.m. local time Friday. “Low lying property and roads are or will be inundated by high tide and wind driven waves,” the Weather Service in Seattle tweeted.
The high water was pushed ashore by a combination of the winds from the atmospheric river and astronomically high or “king” tides. The Weather Service received reports of wind gusts up to 60 mph along the coast and 40 mph around Seattle.
Peak wind gusts over the past hour in mph as strong onshore winds continue to impact the area:
New Dungeness Lighthouse: 59
Smith Island: 57
Tacoma Narrows: 52
Shelton: 51
Port Angeles: 47
Port Townsend: 46
Sea-Tac Airport: 41
Winds will gradually ease this evening.#wawx
— NWS Seattle (@NWSSeattle) January 7, 2022The Bellingham Herald reported that at least a dozen homes were affected by the coastal flooding.
The atmospheric river responsible for the flooding was rated up to a Category 4 out of 5 from the Center for Western Weather and Water Extremes.
The river could be traced as far west as Hawaii; such rivers, due to their tropical connection, are sometimes referred to as the “Pineapple Express.”
Advertisement
Since the fall, atmospheric rivers have repeatedly blasted areas from central California to British Columbia. In the Sierra Nevada, a series of atmospheric rivers in December produced record-setting snowfall, putting a major dent in the region’s drought.
Farther north, especially in the Pacific Northwest and British Columbia, the atmospheric rivers have led to multiple instances of flooding, the most extreme event occurring in November, when high water cut off entire communities.
Quieter weather is forecast for the Pacific Northwest this weekend with just some lingering showers Saturday and dry conditions Sunday.
ncG1vNJzZmivp6x7uK3SoaCnn6Sku7G70q1lnKedZMSmrdOhnKtnYmV%2Fc3uPamZpb1%2BsrrS0yKeeraeeYsC1rdOeZJ%2Bkn6SxqrrGZpqhnZiWuaq%2FjJqtmqSRo7CpsY4%3D