A heavy downpour of rain is causing isolated flooding on Highway 417.
Ontario Ministry of Transportation traffic cameras show flooding in the westbound lanes of the highway near Richmond Road and Bayshore Drive.
Two right lanes and the right shoulder are closed as a result of the flooding.
Ottawa is under a severe thunderstorm watch, with Environment Canada predicting 40 to 70 millimetres of rain by the time the system moves through the region.
Ottawa police also reported flooding at the intersection of Gladstone and Bronson avenues.