From CNN.com:

CALGARY, Alberta (Reuters) -- Flooding forced the evacuation of about 1,500 people in Calgary and swamped or cut off hundreds of homes in the city on Sunday after two rivers overflowed their banks following days of heavy rain.
A state of emergency remained in force for a second day as officials feared the Elbow and Bow rivers that merge in the city -- the center of Canada's oil industry -- could swallow more homes in eight vulnerable neighborhoods.
The rain that has pounded the western Canadian city of nearly 1 million people for more than a week finally stopped on Sunday, but authorities said the danger had not passed.
"It's very extensive damage," Mayor Dave Bronconnier told reporters. "The flows along the Elbow River have peaked and they are currently holding steady, although the flows along the Elbow and the Bow rivers are of extreme concern to us."
"There are literally hundreds of homes that have been impacted. It is still critical," he said. "This is why the mandatory evacuation order has not been lifted.
Despite a major effort by hundreds of city workers and residents to lay sandbags and push dirt on Saturday night, two major roads close to the downtown core were closed as water gushed against bridge decks. The Elbow River in some low-lying districts lapped up above the ground floors of buildings.
It was not clear how many houses sustained flood damage, and Bronconnier said fire department officials would have to survey all the homes in the evacuation areas and confirm they were safe before he lifted the state of emergency.
The volume of water gushing down the Elbow, the smaller of the two waterways, was pegged at seven times the normal amount overnight.
That is because Calgary's main reservoir crested and overflowed the dam that regulates its flow. The Elbow connects with the Bow in the city center.
Much of the rest of southern Alberta dealt with similar problems due to the heavy rains that have swelled rivers and streams throughout the region.
A portion of the Trans-Canada Highway, the country's main motorway, was closed on Saturday west of Calgary because of high water. Cars and trucks were diverted onto a smaller road, leading to a traffic snarl.
About 800 people in the town of Sundre, Alberta, northwest of Calgary, were evacuated on Saturday when their homes were threatened.