Rivers across Western Washington reached record flood levels on December 11, with the Snohomish River, Skagit River, and Cedar River all breaking all-time flood records as a powerful atmospheric river continues to impact the region.
Washington Governor Bob Ferguson declared a statewide emergency on December 10 and deployed the Washington National Guard to assist with disaster response. Ferguson warned at a news briefing that “lives will be at stake in the coming days” and emphasized the unpredictable nature of the crisis.
The floods were triggered by an atmospheric river that was among the strongest and longest-lasting in the history of the Puget Sound region. The storm system delivered more than 15 inches of rain to parts of Washington state in just a few days, with some areas recording over 7 inches of rainfall over 48 hours as of December 9.
Harrison Rademacher, meteorologist with the National Weather Service in Seattle, described the atmospheric river as “a jet stream of moisture” stretching across the Pacific Ocean “with the nozzle pushing right along the coast of Oregon and Washington.”
Forecasters at the Center for Western Weather and Water Extremes predicted the system would reach category five on the atmospheric river intensity scale, indicating an extreme risk of widespread flooding. The moisture plume originated approximately 7,000 miles away near the Philippines, according to NASA data.
The Skagit River emerged as a particular concern, with officials ordering everyone within the river’s 100-year floodplain to evacuate. Some 78,000 people live in the floodplain, according to Skagit County Emergency Management Chief Julie de Losada. The entire city of Burlington and portions of Mount Vernon received mandatory evacuation orders.
Multiple rivers exceeded major flood stage, the highest classification on the National Weather Service scale. The Cedar River at Renton topped 18 feet overnight, breaking its previous record, while the Snoqualmie River near Carnation exceeded 60 feet, causing flooding in Falls City, Carnation and Duvall.
The flooding has paralyzed transportation across the region. Several major highways were closed due to flooding and mudslides, leaving “almost all routes east from the Pacific Northwest” unusable. More than 20 highways remained closed across 11 counties as of Friday morning, including a nearly 50-mile stretch of US Route 2.
Rescue operations have been ongoing throughout the emergency. Eastside Fire and Rescue released video footage of helicopter rescues on Wednesday night showing drivers stranded by floodwaters, with one person climbing atop their vehicle and another seeking refuge in a tree. Pierce County authorities reported conducting more than 25 rescues by Thursday.
Mayor Peter Donovan of Mount Vernon said crews would “be visiting low-lying neighborhoods, residential areas, and getting the word out the best that we can for folks who haven’t responded yet to evacuation notices.”
The remote community of Stehekin, accessible only by boat or aircraft, faces particular challenges. Debris flows from wildfire burn scars severed access to the town, blocking landing zones and boat docks. Chelan County Emergency Management placed the area under evacuation order in preparation for additional rainfall expected next week.
Montana was also affected by the storm system. Governor Greg Gianforte declared a flooding disaster for the northwestern corner of the state on December 11 after the Fisher and Yaak Rivers reached flood stage, impacting Lincoln, Sanders and Flathead Counties.
Over 300 Washington National Guard members were deployed to assist with the flood response, with some conducting door-to-door evacuations in the hardest-hit communities. The American Red Cross has opened several volunteer-led shelters across the state.
“When I was sitting up in my office, I could just see it start coming up,” Colton Petit, owner of Reliable Concrete Pumping in Snohomish, said while describing watching floodwater rush into his shop. “There’s nothing you can really do.”
Weather forecasters warned that while the initial atmospheric river system has weakened, additional storms are expected to bring more rain starting Sunday and continuing into the following week. The already saturated ground and swollen rivers remain vulnerable to rapid rises from even moderate rainfall.
Atmospheric rivers account for 30 to 50 percent of the annual precipitation observed in the Pacific Northwest, though most events are weaker than the current system. Scientists indicate that such events are likely to increase in frequency and severity due to human-caused climate change.
The current disaster follows other significant flooding events in the region, including the 2021 Pacific Northwest floods and the 2024 British Columbia floods, both caused by atmospheric river systems.
Authorities continue to urge residents to heed evacuation orders and avoid attempting to drive through floodwaters. Washington Emergency Management Director Robert Ezelle cautioned residents against returning to their homes prematurely, noting that the situation remains fluid and dynamic.
