Orillia firefighters were called to Queen St between West and Front after heavy rain caused localized flooding, shut down the road and trapped a motorist in his car.
"We had an enormous amount of rain and I believe that location is a problem area for the city," said Deputy Fire Chief Jeff Kirk. "It flooded out. People weren't paying attention to the barricades that were up and some gentleman went down and his car was submerged."
Kirk says the Orillia Public Works Department had barricaded the road because of the flood.
"It would've probably been three feet deep in that area," said Kirk.
Firefighters used ropes and personal flotation devices to extricate the man in the swamped car.
"He was already climbing out of his car when we got on scene," Kirk said, adding a reminder to motorists to respect barricades.
The rainfall warning has been cancelled for Barrie and the surrounding area.
Amounts of 40 to 60 mm of rain were likely, according to Environment Canada.