But police say they have since pulled back the search as they believe the man has drowned.
Two men in their early 20s were spotted in the water, in the Deschenes Rapids, around 4 p.m. Sunday, after their small inflatable dinghy flipped in the rough conditions.
Emergency crews from Ottawa and Gatineau were called in to assist with the rescue efforts and one man — who was wearing a life jacket — was brought to shore by Gatineau water rescue crews.
Fire crews on both sides of the river called off their search around 9 p.m.
Ottawa police say they conducted an extensive search that included divers and sonar equipment but were unable to find the man or the green and yellow "Seahawk" dinghy.
The names of the two men were not immediately released.
(CFRA, The Canadian Press)