An aerial view of the Red River valley south of Winnipeg, showing a lake where farmland should be. (CBC)

The flood of 2009 has become Manitoba's third worst in 100 years — and it's not even over yet.

Manitoba Emergency Measures Minister Steve Ashton made the announcement during a news conference Tuesday afternoon.

The events of the past three weeks and sheer volume of water have surpassed the 1979 flood, he said.

"As of today, this flood — and it's most definitely not over yet — is the third worst flood of the century," Ashton said.

The crest, which is currently in the Emerson area near the Manitoba-U.S. border, is not expected to reach Winnipeg until next week.

It is anticipated the crest will be in Morris, about 70 kilometres south of Winnipeg, on Friday. Already that town is an island in a lake that spreads 16 kilometres wide in places.

Massive ring dikes are keeping the flood waters from swallowing Morris and other towns along the river's path.

Only two floods have been worse in Winnipeg. The one in 1950, prior to the floodway being built, and the 1997 flood, which put thousands out of their homes and brought the military to Manitoba to help.

North of Winnipeg, where dozens of homes have been flooded and some destroyed by massive blocks of shifting ice, this is the worst flood on record, said Ashton.

Flood officials said there is water coming from everywhere — provincial tributaries and the Red River — and the problems are spread across Manitoba.

The only place not facing the possibility of high water this spring is The Pas, 730 kilometres northwest of Winnipeg, near the border with Saskatchewan.