Officials are warning about an obstruction on the Upper McKenzie River below Paradise Campground. It's at milepost 52 on Highway 126, which parallels the river.
A large tree trunk and smaller debris are completely blocking the river.
The Lane County Sheriff's Office said it cannot be passed safely, and there are no safe portage options.
The public is asked to avoid this section of river or navigate with extreme caution.
Marine Patrol deputies are coordinating with the Forest Service on a plan to remove or mitigate the obstruction.
The blockage coordinates are 44.17802, -122.13255.
Visit oregon.gov/osmb for the latest information on water obstructions within Oregon.