The incident was reported about 2:30 p.m., south of Twin Rivers Park, along Jordan Road, said Silvana Fire Chief Keith Strotz.
The jet ski apparently struck the river bottom, and the man was thrown over the top, Strotz said. The man suffered a broken leg.
The Stillaguamish Water Rescue Team rushed the man to the park, where an ambulance was waiting to take him to the hospital.
Crews responded from the Arlington Rural, Silvana, Granite Falls, Oso and Darrington fire districts.
Most recent Sirens posts
Our new comment system is not supported in IE 7. Please upgrade your browser here.