About
Green River, Washington — 1862 Howard Hanson Dam 1962, 1911 Tacoma Diversion, Flaming Geyser 1971. From the Cascade headworks to Auburn, the Green River drops 65 miles through King County on flows averaging 1,600 CFS with an optimal range of 500–3,000. The Green River Gorge section between Kanaskat and Flaming Geyser offers the best whitewater — Class II–III drops through a protected conservation area that keeps the corridor undeveloped. Above the gorge, the upper Green runs Class I–II from the headworks to Kanaskat as a mountain river. Below Flaming Geyser, the lower Green flattens to Class I for an urban float to Auburn. The Duwamish and Muckleshoot peoples knew this as their Green River, and recent conservation efforts in 2020 established the Green River Gorge as an Urban Wilderness Revival area. Northwest Whitewater Association coordinates access and runs. USGS gauge 12113000 tracks flows that can swing dramatically with Cascade snowpack and rainfall.
River conditions are community-verified. CFS ranges, difficulty ratings, and access points may not reflect every flow level or seasonal change. Always check current conditions, scout unfamiliar rapids, and paddle within your skill level.