12/18/2025
The most severe flood in Renton's recorded history occurred on November 19, 1911. The "then" photo looks west from 2nd St and Burnett Ave. Two boys are walking on a wood sidewalk as muddy water flows on both sides. In the background is the original Renton High School building constructed that year. In the "now" photo, the original building is gone, replaced with larger school buildings and the Ikea Performing Arts Center.
The second "then" photo shows a flooded Downtown and North Renton viewed from Renton Hill. Bronson Way bridge is on the right. In the distance, the Northern Pacific Railroad tracks are just above the floodwaters (running left to right). The tracks ran parallel to today's Logan Ave and it crossed the river at the Renton Senior Activity Center, where a huge log jam formed that needed to be cleared.
The flood was caused by heavy rains and mountain snow melt from warm winds. Residents were warned that a timber crib dam located 14 miles upstream at Landsburg was at risk of failing. The dam was built in 1899 to divert water into pipelines supplying freshwater to the City of Seattle. The upper portion of the dam failed, and while it didn't create a flash flood situation in Renton, it did destroy a bridge carrying the pipelines causing a Seattle-wide water outage that lasted for a week.
After the flood, citizens voted to create King County Commercial Waterway District No. 2, which straightened and dredged the Cedar River to improve flood control. Seasonal floods continued to occur outside of the downtown area, usually near Renton Airport, Earlington Flats (the area between the Green River and Hwy 167), and along the Cedar in Maple Valley. Major flood events occurred in 1926, 1932, 1946, 1952, 1976, 1990, and 1996. In 1998-99 the City and US Corps of Engineers dredged the river and built levees and floodwalls near the airport/Boeing to protect against the 100 year recurrence flood. The City continues to monitor the sediment levels and perform maintenance dredging to mitigate flood risk.
Photos courtesy of Renton Historical Society, colorized
The map on the last page, without my notes, can be found at https://info.kingcounty.gov/transportation/kcdot/roads/mapandrecordscenter/mapvault/ (Folder A-119, Map Number 3-42.a)