Roseau River First Nation and the hamlet of Riverside will likely be evacuated in the next few days, and large portions of Highway 75 could close sometime next week as flood waters close in on Manitoba.

But the forecast is not much worse than it was last week, despite heavy rain turning to snow this week from Winnipeg to Fargo, provincial flood forecaster Alf Warkentin said Monday.

There is still only a 10 per cent chance of a 1997-magnitude flood of the century, Warkentin told a news conference, but we're still facing a very serious 1979-scale flood throughout the Red River Valley.

"The moment of truth is getting closer," he said.

Warkentin expects the Red River will crest at Emerson from April 5 to 10, and at Winnipeg April 12 to 17.

The impact will hit a few days before the crest, which means anyone driving south during school break next week would have to drive west to find a way into the U.S. -- and Highway I-29 south from the border to Grand Forks and Fargo will likely be closed.

Communities and roads could feel the impact as early as April 1 in southern parts of the province, and it could take 10 days after the crest passes before southern Manitoba starts to get back to normal.

The 800 people in Roseau River First Nation and 55 people in Riverside will be evacuated, because all roads around them are expected to be under water, said Steve Topping, head of Infrastructure and Operations Division at Water Stewardship. Only essential personnel will stay behind.

Another 11 communities will have only one way to travel beyond the safety of their ring dikes.

Manitoba highways information manager Neil Gobelle said Highway 75 will close completely from Provincial Road 205 to St. Jean Baptiste, and Highway 75 will have only local access from Winnipeg to 205, and from St. Jean Baptiste to Highway 14.

About 21 stretches of major roads will close once the water arrives.

Don Brennan, acting director of Manitoba Emergency Measures Organization, said that the Manitoba Association of Native Firefighters will handle the Roseau River evacuation. "They do this quite frequently with forest fires," he pointed out.

In last week's forecast, Warkentin said, "We had most of that precipitation in there that we're getting now."

While western Manitoba received up to 60 millimetres of rain since Sunday, Warkentin said, it was more like 10 mm along the Red River. "It didn't produce all that much in the Red River basin, thank goodness."

Another storm moving up from Nebraska will bring heavy rain turning to snow, but several factors are helping Manitoba, Warkentin said.

Warm temperatures are bringing us an early run-off, before Fargo's expected-record flood level gets here. Freezing temperatures later this week will then slow our run-off while water starts to arrive from North Dakota.

"We'll get rid of a lot of our run-off before the crest from the U.S. gets here," Warkentin said.

"We're looking at 25 to 50 mm of rain from Grand Forks to Winnipeg over the next couple of days, followed by snow," he said. "It appears the bulk of it will be north of Grand Forks to Winnipeg, which is good news for the folks of Fargo."

Topping was confident that all the communities from Emerson to Winnipeg would be able to withstand the water. "The ring dikes are all built to 1997 plus two feet levels," with pumps inside the dikes, he said.

"The Floodway can easily handle that amount of flow," Topping said.

Warkentin cautioned that having a 1979-scale flood is still very serious, and said that if Manitoba gets two or three major storms in the first two weeks of April, we could still get close to the 1997 levels.

"The 1979 flood was very bad," Warkentin said.

Gobelle said that it will add about an hour a trip for commercial trucks to use highways 2 and 3 from Winnipeg to get around the flooded areas and reach the U.S. border.

But, from there, "A lot of this is based on what happens to I-29," and how flooding from Fargo to the border affects American highways.

Brennan said that communities with ring dikes believe they have sufficient staff and local volunteers to sandbag, without asking for volunteers from a wider area.

Provincial health and education departments are ready to deal with any students unable to get to school or residents of personal care homes affected by flooding, Brennan said.

Topping said that there will be a pass system for anyone living within the flood plain, so that emergency services can account for everyone going in and out once the flood comes.

Brennan said that provincial officials will conduct a conference call with affected communities this morning, and will hold a flood forum in Boissevain Wednesday.

Warkentin said he is now issuing daily flood forecasts for the Red, and will soon be announcing forecasts for the Assiniboine, Souris and Pembina basins.

nick.martin@freepress.mb.ca