Channel Migration Areas in King County

Channel migration hazards for seven King County rivers: Middle White River, Raging River, Tolt River, Three Forks area of Snoqualmie River, Cedar River, Green River, and the South Fork of the Skykomish River. The Cedar River was updated April 2015, the SF Skykomish June 2017, and the Tolt July 2018. In December 2019, the Middle White River was added, the Raging River was updated, and a revision was made to the updated Cedar CMZ. The Lower Snoqualmie CMZ was added November 2025 after adoption by the Dept. of Local Services.