Dam breach in Washington triggers life-threatening flash flood warnings; evacuations urged
Levee breach south of Seattle prompts widespread alerts across Puget Sound as rain continues and rivers rise
A dam breach on the Green River Levee south of Seattle triggered a life-threatening flash flood emergency Monday as heavy rainfall drenched western Washington. The National Weather Service issued a FLASH FLOOD WARNING at 11:51 a.m. PT after the breach near Tukwila, prompting evacuations across a broad swath of the Puget Sound region. The warning covers 12 counties: Clallam, Grays Harbor, Jefferson, King, Kitsap, Lewis, Mason, Pierce, Skagit, Snohomish, Thurston and Whatcom.
Officials said more than 46,000 people could be affected, with two schools and one hospital in the flood zone. Residents east of the Green River in the Orillia area near Tukwila, Renton and Kent were under Level 3 (Go Now) evacuation orders. State and local authorities said about 1,100 residents had received emergency notifications to move to higher ground. Water was moving north toward Interstate 405. The breach is tied to days of intense rainfall, and another round of heavy rain was forecast to bring up to 12 inches in some areas.
Forecasters said flash flooding was already underway and the damage threat was considerable. The Pineapple Express, a warm atmospheric river, was delivering moisture from the tropics, with two to four inches of rain expected, and a possible 12 inches on windward slopes. Officials warned that additional rainfall on saturated ground would raise the risk of mudslides and worsening runoff through midweek.
AccuWeather meteorologists warned that rivers could crest in multiple rounds, with rapid rises in higher elevations and slower, prolonged flooding in lower terrain. Several inches of additional rain this week could renew major flooding on rivers that recently crest.
The dam failure is seen as a result of the recent heavy rainfall in Washington, with forecasts calling for more rain Monday and through midweek. Rivers in western Washington are already rising, and officials warned that additional crests could occur in the coming days. Authorities urged residents to heed evacuation orders and avoid floodwaters, as water can move rapidly and unpredictably.
Officials are coordinating with county agencies to monitor levee stability and river levels and to issue updates as conditions change. The weather pattern is expected to persist through midweek, prolonging the risk of floods and landslides even after the rain ends.