An intense atmospheric river has strengthened over western Washington, bringing heavy rain and the risk of historic, possibly catastrophic, flooding that could force as many as 100,000 people to evacuate.
Forecasters warned that after two days of steady rain another 4 to 8 inches could fall Wednesday and Thursday in higher elevations of western Washington. Gov. Bob Ferguson declared a state of emergency Wednesday, urged residents to follow evacuation orders and called the situation extremely serious. Officials said some rivers could reach historic levels as early as 4 a.m. Thursday and remain high into Friday morning.
Skagit County issued immediate evacuation orders for Mount Vernon and upriver communities including Hamilton, Rockport, Marblemount and Concrete, and warned that residents in the 100-year floodplain would likely receive notices. County leaders also announced closures for nonessential government services, including district and superior courts, due to flooding and hazardous conditions.
The National Water Prediction Service forecasted 18 major floods and 15 moderate floods across Washington, a pattern county officials described as historic. Gov. Ferguson said catastrophic flooding is likely.
Eastside Fire and Rescue assisted with water rescues after flooding and a landslide affected residents, reporting the rescue of three adults with limited mobility and a dog from a flooded house on the Middle Fork Snoqualmie River. A landslide also blocked eastbound lanes on I-90.
Most rivers in the region are expected to reach moderate to major flood stages. Record flooding is possible on several waterways, notably the Skagit River at Mount Vernon and Concrete, which could crest 3 to 5 feet above previous records starting Thursday afternoon and continuing through Friday. Senator Maria Cantwell said she was alarmed after speaking with the National Weather Service about the Skagit’s potential to exceed its record crest and urged people to evacuate when told to do so.
The Snoqualmie River between Snoqualmie and Carnation is forecast to continue rising through Thursday morning, reaching major flood stage and inundating farmlands, roads and residential areas from Snoqualmie to Fall City to Carnation. US-12 is already underwater in spots and the town of Randle has been cut off.
Amtrak suspended train service between Seattle and Vancouver for Thursday and Friday because of Skagit River conditions. While heavy rain is expected to ease by Thursday afternoon, many rivers will take several days to fall back. Northern Idaho and Montana could see heavy rain and localized flash flooding over the next 24 hours.
Residents in threatened areas are being urged to move to higher ground, follow evacuation orders, and avoid flooded roads until authorities declare it safe to return.