Two women and a rafting guide, all in their 30s, from the Dortmund region in western Germany were in France as part of an adventure sports group, gendarmes said on Thursday.
The group were rafting down the Baou canyon, a popular spot for beginners, on Wednesday when the gorge was swamped by a wall of water two to three metres (seven to 10 feet) high, laden with tree branches and debris, gendarmes said.
Caught by the flood, they were unable to sound the alarm until hours later when one of them managed to struggle out of the water. Emergency services, using a helicopter, recovered three bodies at the foot of a waterfall just before nightfall.
The survivors were said to be in a state of shock and one young woman was hospitalised suffering from hypothermia. Local authorities banned white water sports on the upper stretch of the Verdon River due to stormy weather conditions, but it remained authorised in the Baou canyon.