Residents in low-lying areas of Calgary are being told to leave their homes as flood waters rise.
Officials are going door to door in six communities to order people out and assist them to higher ground.
Residents are being warned they could be out for at least three days.
Calgary and most of southern Alberta are being hammered by rain that has washed-out roads and bridges, caused mudslides and closed major highways.
The affected Calgary communities are: Mission, Stanley Park, Elbow Park, Roxboro, Rideau and Discovery Ridge.