An embankment holding back water on a tributary of Birdtail Creek is giving way, meaning a surge of water is expected to travel quickly down the creek and flood communities downstream, according to the provincial government.
The Waywayseecappo and Birdtail Sioux First Nations and the rural municipalities of Birtle, Rossburn and Miniota, as well as the Town of Birtle, are making flood preparations, according to the province.
As of Sunday morning, nine houses in Birtle, and another two in the rural municipality, are being evacuated as a precautionary measure, local officials announced Sunday morning.
Ron Bell, the emergency measures public information manager for both the town and the RM of Birtle, told CBC News the flooding could begin at any time, so crews are putting dikes and water tubes in place.
The situation in Birtle is unusual, said Bell, who noted that while the local park floods annually, homes don't usually have to be evacuated.
"It's really hard to plan for this; this isn't a scenario that has come before," he said Sunday.
The Rural Municipality of Birtle and the town declared states of local emergency on Saturday, after the province issued a flood warning for Birdtail Creek.
Water could go over some roads in the area, and flood officials worry that some bridges in the town of Birtle could be damaged.
Bell said the creek's normal spring crest has likely passed, but the big problem is the oncoming surge of water from the failing embankment.
"It appears the river right now here is going down a little, which is good. The more it goes down, the better it'll be here because it'll allow more capacity for the water that's coming," he said.
"But a big release of water all at once is not something we've had to deal with."
First Nation homes, businesses at risk
Some members of Waywayseecappo First Nation also started leaving on Saturday night as a precaution.
One home was evacuated on Saturday night and at least four homes in low-lying areas, as well as a seniors' residence, are being evacuated on Sunday morning, Waywayseecappo Chief Melville Wabash told CBC News.
Evacuees are being sent to temporary accommodations in Russell, Man., he said.
Wabash said the band is worried that several essential buildings are at risk of flooding, including a grocery store, daycare building, convenience store, and even the local RCMP detachment and band office.
"We're very concerned that it's going to displace a lot of our people, a few people, if it does break," he said Sunday morning.
"If EMO is saying that there is that much water behind that dam, it's going to affect our businesses."
Flood officials say a culvert blocked by ice has caused a significant buildup of water behind the old railroad embankment, just upstream of Highway 45.
Depending on how major the breach is, forecasters believe water flows on Birdtail Creek are expected to be as high as 30,000 cubic feet per second.
Wabash said a dam along the Trans-Canada Trail is already starting to deteriorate.
"The one side of the rail bridge or the dam has given way already, and once that gives, it's going to be a big threat to the valley," he said.
Highway 45 from 264 to 476 is closed in anticipation of high water. Traffic is being routed back to Highway 16, and flag staff are being stationed in the valley to prevent traffic from entering the possible flooding area.