A farmyard just outside St. Jean Baptiste, south of Winnipeg, has been turned into an island surrounded by water. (Bert Savard/CBC)

The flood forecast for Manitoba keeps getting worse, with officials announcing on Wednesday that the peak flow of the Red River in Winnipeg will exceed the flood of 1950.

'It's a very serious concern for the city.'— Alf Warkentin, Manitoba's chief flood forecaster

The province's chief flood forecaster, Alf Warkentin, said Wednesday the anticipated crest level for Winnipeg is more than a half-metre higher than what officials were predicting on Tuesday.

"It's a very serious concern for the city," he said at a flood briefing.

The crest, expected to pass through the Winnipeg within the next couple of days, is forecast to be 6.78 metres. Only the flood of 1997, with a crest of 7.47 metres, was worse in the past 100 years.

If not for the floodway diverting water around the city, the 2009 crest would actually be 9.1 metres, officials said.

Up to 1,000 people asked to leave homes

A voluntary evacuation notice has also been issued by the rural municipality of Ritchot, just south of Winnipeg.

The notice affects up to 1,000 people in the area, including 40 residents of a personal care home in St. Adolphe.

'If they feel uncomfortable, are a little older or they have some kind of medical condition, they should take serious consideration to this [evacuation notice].'— Ritchot Mayor Bob Stefaniuk

Ritchot Mayor Bob Stefaniuk said the decision to issue the notice was made as a precaution, to ensure people are not putting themselves at risk.

"They're under a situation where they're losing [road] access. We have about 150 homes that are isolated because of road closures and the river is going up every day," he said. "If they feel uncomfortable, are a little older, or they have some kind of medical condition, they should take serious consideration to this."

Anyone who needs help leaving home can call the RM's emergency operations centre at 883-2633.

Once in Winnipeg, evacuees are asked to register at the Century Arena on Clarence Avenue.

Volunteers answer the call, but more needed

More than 800 volunteers have registered to assist with sandbagging efforts in Winnipeg, answering the city's plea.

Officials put out the call late Tuesday after revised flood forecasts left 100 homes in need of extra flood protection. Although the initial plea was for 500 to 600 volunteers, the city announced after Wednesday's latest flood forecast that 800 people have come forward and even more are needed.

The most at-risk properties are on Scotia Street in West Kildonan and Glenwood Crescent in Elmwood, the city said in a news release.

The volunteers are needed immediately to work into the evening.

Anyone willing to help is asked to email their name, telephone number, and times of availability to 311@winnipeg.ca or call 311. Volunteers will be advised on where to report.

Crest clarity

The crest that will pass through the city this week is not the crest of the floodwaters that passed through North Dakota.

'All the worst-case scenarios are coming at us at the same time.'— Randy Hull, emergency measures co-ordinator

This year is an anomaly in that it will have three distinct flood crests, rather than the usual one. The first crest hit the city last weekend, when the Red River surged over its banks because ice jams impeded its progress.

The current crest was caused by a combination of rain in the past week, along with 18 C temperatures that have caused rapid melting. As a result, many of the rivers in southern Manitoba have become swollen.

Several of those rivers are tributaries that feed into the already-bloated Red River — and the crests of those rivers are all reaching the Red in the next day or two.

"All the worst-case scenarios are coming at us at the same time," said Randy Hull, Winnipeg's emergency measures co-ordinator.

The North Dakota crest waters are expected to reach Winnipeg next week.