The southern Manitoba landscape is dotted with islands of raised properties and sandbagged communities. (CBC)

The expanse of southern Manitoba that is swamped by flood waters is, in fact, twice as big as what flood forecasters had been saying over the past three days.

Officials had been saying the Red River had spread across an area of 800 square kilometres in southern Manitoba. On Monday, they said 1,680 square kilometres are actually under water.

During the so-called flood of the century in 1997, the river's span was 2,000 square kilometres — an area equivalent to the size of Prince Edward Island.

More than 2,200 people have been forced to leave their homes as the Red River and other tributaries in Manitoba have spilled over their banks and through communities, highways and farmland.

The crest of the flood is between Morris and St. Adolphe, about 60 kilometres south of Winnipeg.