Residents in the Pacific Northwest of the United States and Canada are bracing for potentially record flooding as an atmospheric river dumps heavy rain on already swollen rivers.

The National Weather Service warned of the potential for catastrophic flooding along the Skagit and Snohomish rivers in Oregon and Washington.

In Canada, major highways into Vancouver were closed due to the risk of flooding, debris and avalanches.

The United States and Canada have issued evacuation orders for thousands of people, and authorities warned of more rain on Thursday.

In the United States, Washington State Governor Bob Ferguson announced State of emergency On Wednesday, an estimated 100,000 residents may soon face evacuation orders.

The emergency declaration warned that continued rain and snow in the mountains would worsen flooding conditions. Supply chains and transportation could be severely affected, the statement added.

Skagit County, a largely agricultural region north of Seattle, issued an immediate evacuation order for residents in floodplain areas.

About 75,000 people will be evacuated from low-lying areas of the Skagit River, Robert Ezell, director of emergency management at the Military Department in Washington, told reporters on Wednesday.

The Snohomish County Sheriff’s Office said in an overnight social media post that it had rescued “multiple people” who were trapped at their home in Sultan, Washington, a community about 40 miles (65 kilometers) northeast of Seattle.

The Sheriff’s Office warned residents on Thursday morning that water levels in the Skykomish River reached more than 24 feet (7m) overnight, just below record levels, with the eastern part of the county being hardest hit.

The Snohomish River was also experiencing severe flooding, they said, with a “record-setting dance” as the water crashed against local flood walls.

Officials in King and Snohomish counties said there were multiple closures of state and local roads and more closures were possible Thursday.

The Pierce County Sheriff’s Office said in a video Wednesday that its rapid-fire crews had to rescue three people from an RV park in the Alting community, about 42 miles south of Seattle. Many roads in the county were also closed.

Across the border in British Columbia, Canada, evacuation orders have been issued for the communities of Tulameen and Eastgate. several other areas.

The City of Abbotsford ordered an emergency evacuation of 371 properties at 23:00 local time on Wednesday (07:00 GMT on Thursday).

City officials said the Nooksack River was expected to overflow its banks early Thursday and said they did not expect flooding to be as severe as in 2021 in the province, when flooding caused significant damage and killed five people.

According to the travel information website Drive BC, all major highways into the Lower Mainland are now closed.

The U.S.-Canada Sumas border crossing is also closed in both directions.

Entire regions across parts of the United States and Canada were hit by torrential rains from atmospheric rivers, a phenomenon in which water evaporates into the air and is carried by the wind, forming long streams of water that surge across the sky much like rivers flow on land.

The heaviest rainfall is expected to subside by Thursday afternoon, but water will continue to flow into rivers.

Another storm is expected on Sunday.