By Steven Schauer, Deputy Executive Director
This Flood Event Report documents the historic flooding that impacted King County between December 8 and December 30, 2025. The December 2025 flood was one of the largest King County has experienced in decades, establishing several new flood event records. Given the scale of this significant flood, additional technical assessments, damage evaluations, and financial summaries are still being developed and will be provided in follow-up reports as recovery and inspections continue.
“King County experienced an extraordinary flood event from December 8 through the 30th,” said King County Flood Control District Chair Reagan Dunn. “Despite the severity and duration of this storm, we are deeply grateful that there was no loss of life in King County. This outcome reflects the Flood Control District’s 18 years of sustained investment in flood risk reduction infrastructure, including the completion of 123 capital projects and the investment of over $623 million in flood risk reduction. These projects were designed and constructed not just to withstand floods, but to help protect people, property, and critical infrastructure.”
The King County Flood Control District also recognizes the immense effort required to monitor and protect flood infrastructure during this event and in its aftermath.
Vice Chair Sarah Perry said, “We extend our sincere thanks to the first responders, field crews, engineers, and public works teams from King County, local jurisdictions, and state and federal partners who worked tirelessly, often in dangerous conditions, to monitor infrastructure and implement emergency measures throughout this flood. During the flood event, the King County Flood Control District provided nearly $3 million for emergency flood mitigation and repairs, and we continue to work closely with our partners to expedite recovery efforts, including by providing close to $7.3 million in post-flood funding to support urgent levee and revetment repairs.”
Flood Event Report
This report is preliminary and only intended to provide a high-level review of the flood and associated activities. Due to the magnitude, geographic extent, and prolonged duration of the December flood event, this report follows a modified format as compared to past flood event reports from the King County Flood Control District.
Rather than organizing impacts by river basin, this report includes an Executive Summary followed by a chronological listing of information related to this flood event. Each day on the chronological list includes a top-line daily summary and additional details to provide a deeper look at how the flood event unfolded over three weeks of sustained rainfall, multiple atmospheric rivers, dam releases, and extended flood operations. The report ends with a post-flood event path forward and a section providing recognition to our governmental partners for their incredible work during this historic flooding.