Why the National Weather Service Canceled the Green River Levee Flash Flood Warning After Successful Breach Containment
The immediate crisis for west-central King County residents subsided on Monday evening, December 15, 2025, as emergency officials announced that the life-threatening Flash Flood Warning has been lifted. The cancellation of the warning and the subsequent lifting of "Go Now" evacuation orders came after a frantic day of emergency repairs on the Desimone Levee along the Green River, which had suffered a critical breach earlier that afternoon.
The immediate status and summary of the incident began just before noon on Monday, when the National Weather Service (NWS) issued a dire warning after a section of the levee near South Todd Boulevard in Tukwila gave way. The breach sent river water at its highest level in 60 years rushing into nearby industrial and commercial zones, prompting a Level 3 "Go Now" evacuation for approximately 1,100 homes and businesses in parts of Tukwila, Kent, and Renton. However, by 7:30 p.m., King County Emergency Management confirmed that temporary repairs had been successful, and the flash flood warning was officially canceled.
Key stats and details regarding the breach revealed that a "car-sized chunk" of the earthen levee was washed away by the swollen river, which had reached flows of over 12,000 cubic feet per second due to a series of atmospheric rivers. Crews from the U.S. Army Corps of Engineers and local agencies worked rapidly to plug the gap with "super sacks" large nylon bags filled with a ton of sand each. While the initial warning area covered nearly 47,000 people, it was narrowed significantly as officials determined the flooding was largely confined to small industrial areas. No injuries were reported.
The strategic factor in the Green River levee emergency was the extreme saturation of the levee system following more than a week of relentless rain. King County crews had actually been on-site installing a "seepage blanket" to stabilize the structure when the breach occurred, allowing for an almost instantaneous emergency response. The Desimone Levee, which was already scheduled for long-term repairs following damage in 2020, remains under close watch, as the ground is so thoroughly soaked that officials warn further breaches remain possible with more rain in the forecast.
The future outlook for King County residents involves a transition from immediate emergency to long-term vigilance. While the evacuation alert has been lifted and it is safe to return to the Orillia area, the region remains at a "Ready" Level 1 alert. A broader flood warning still exists for the Green River near Auburn and the Cedar River in Renton. Residents are urged to avoid standing water, respect all road barricades, and stay tuned to emergency alerts as a new storm system is expected to arrive later in the week.