Record flooding threatens Washington as more heavy rain pounds Northwest

Residents packed up valuables and prepared to flee rising rivers in Western Washington state on Wednesday as a new wave of heavy rain swept into a region still reeling from a storm that triggered rescues and road closures a day earlier.

In the Pacific Northwest, an atmospheric river was swelling rivers toward record levels, with major flooding expected in some areas including the Skagit River, in a major agricultural valley north of Seattle. Dozens of vehicles were backed up at a sandbag-filling station in the town of Mount Vernon as authorities warned all residents who live within the river's floodplain to be ready to evacuate.

"We're preparing for what increasingly appears to be a worst-case scenario here," Mount Vernon Mayor Peter Donovan said.

In the Mount Rainier foothills southeast of Seattle, Pierce County sheriff's deputies rescued people at an RV park in Orting, including one man in a Santa hat wade through waist-deep water. Part of the town was ordered to evacuate over concerns about the Puyallup River's extremely high levels and its upstream levees.

Washington Gov Bob Ferguson declared a statewide emergency Wednesday. "Lives will be at stake in the coming days," he said.

"It's time to pay attention," said Gent Welsh, adjutant general of the Washington National Guard.

Hundreds of Washington National Guard members will be sent to help communities, Welsh said.

The Skagit River is expected to crest at roughly 47 feet (14.3 metres) in the mountain town of Concrete early Thursday, and roughly 41 feet (12 metres) in Mount Vernon early Friday morning.

Those are both "record-setting forecasts by several feet," Skagit County officials said.

Mount Vernon, the largest city in the county with some 35,000 residents, completed a wall in 2018 that helps protect the downtown from flooding. But the city -- parts of which are in the floodplain, including commercial areas -- is on high alert.

"With a flood of of the magnitude that's predicted here in the next couple of days, I'm concerned about all of our buildings in the city in the floodplain," said Donovan, the mayor.

Harrison Rademacher, a meteorologist with the weather service in Seattle, described the atmospheric river soaking the region as "a jet stream of moisture" stretching across the Pacific Ocean "with the nozzle pushing right along the coast of Oregon and Washington."  Authorities in Washington have knocked on doors to warn residents of imminent flooding in certain neighbourhoods, and evacuated a mobile home park along the Snohomish River. The city of Snohomish issued an emergency proclamation, while workers in Auburn, south of Seattle, installed temporary flood control barriers along the White River.

Along Interstate 5 between Seattle and Portland, firefighters on Tuesday rescued people who tried to drive on flooded roads, including a semi-truck driver, said Malachi Simper, spokesperson for Lewis County Fire Protection District 5. Authorities rescued a family of six from their home in Chehalis, he said, where the road was covered by about 4 feet (1.2 metres) of water. No one was injured.

Another storm system is expected to bring more rain starting Sunday, Rademacher said. "The pattern looks pretty unsettled going up to the holidays.