An atmospheric river event that’s been slamming the Pacific Northwest with rain is now focused on western Washington, where “historic” flooding could force 100,000 people to evacuate.

After two days of rain, another 4 to 8 inches of rain is possible Wednesday and Thursday in the higher elevations of western Washington state.

Washington Gov. Bob Ferguson announced a state of emergency on Wednesday and he pleaded with residents to follow evacuation orders.

“The situation is extremely serious,” he said at a news conference.

In a statement posted on X later Wednesday evening, Ferguson said state officials anticipate potentially 100,000 state residents could face evacuation orders.

“The situation is fluid and changing all the time. We expect rivers to hit historic levels as early as 4 a.m. tomorrow, lasting into Friday morning.”

Skagit County officials said on Wednesday that upriver communities, including Rockport, Hamilton, Marblemount and Concrete, “are recommended to evacuate to high ground as soon as possible,” calling the flooding predictions “historic.”

Eastside Fire and Rescue, which services King County, posted on X that they assisted with water rescues on Wednesday as flooding and a landslide impacted residents.

Three adults with limited mobility and a dog on the Middle Fork Snoqualmie River were rescued due to their home flooding, and a landslide on the eastbound I-90 blocked lanes, officials said on X.

Most rivers in the region are forecast to reach moderate or major flood stages. Record flooding is forecast for some rivers, especially the Skagit River at Mount Vernon and Concrete, Washington, which could swell 3 to 5 feet above record levels beginning Thursday afternoon and continuing through Friday.

In a post on X, Washington Sen. Maria Cantwell said she had spoken with the National Weather Service and was “alarmed” to hear the Skagit River could peak as high as 5 feet above its record crest level. “Please please please stay alert and follow evacuation orders,” she posted. “This is not just another flood.”

The Snoqualmie River, between Snoqualmie and Carnation, will continue to rise through Thursday morning, reaching major flood stage and bringing flooding to farmlands, roads and residential areas from Snoqualmie to Fall City to Carnation. 

US-12 is already underwater in a number of areas and the small town of Randle has been cut off, officials said Wednesday.

Amtrak said trains are suspended between Seattle and Vancouver on Thursday and Friday due to the level of the Skagit River.

While the heavy rain will be over by Thursday afternoon, some rivers will take several days to fully recede. 

The heavy rain will also impact northern Idaho and Montana over the next 24 hours, with localized flash flooding possible.