Fears about an embankment collapsing and sending a surge of floodwater into some western Manitoba communities ended with the boom of an ice-plugged culvert Wednesday morning.

The 30-metre-high ridge near Waywayseecappo First Nation had been growing weak from the pressure of holding back the swollen Birdtail Creek.

The creek had turned into a raging river, engorged by the plugged culvert which prevented spring run-off from flowing away.

Waywayseecappo flooding

Volunteers build sandbags at Waywayseecappo First Nation on Tuesday, but their work had to be abandoned after a culvert gave way. (CBC)

Richard Shingoose was standing near the embankment when the ice finally shot out of the culvert like a cannon ball at 12:30 a.m.

He said it sounded like an explosion, followed by a gush of water that rushed down the hill and into the valley.

Immediately, the water levels on the creek began to recede and by 7 a.m., the levels had dropped to normal behind the embankment, the provincial government said.

While that is good news now, the sudden rush caused panic in Waywayseecappo.

Band Coun. Barb Cameron said workers who were making sandbag barriers to protect the community's business centre had to leave before finishing the work, worried they would get trapped.

But Shingoose and nine others raced down to the community to finish it, which they managed to do by about 6 a.m.

He said it was a difficult task at times as the water started arriving, flowing over some roads including Highway 45. They almost gave up, but managed to complete the barricade and have the water contained, Shingoose said.

Parts of the Birdtail Creek embankment had been eroding away since the weekend. There are two sections where portions of the mud wall slid down.

Water began seeping through the weakened sections, raising concern the entire embankment could collapse and send a surge of water into the valley, first through Waywayseecappo and then the town of Birtle.

As a result, more than 100 people were forced to leave their homes in those communities.

The province brought in an excavator to cut a section into the embankment — a former railway ridge — overnight Monday into Tuesday.

The cut was made to release some of the trapped water and relieve the pressure on the dike.

Crews were able to control the rate of the release so no communities were inundated. The release on Wednesday of the blocked culvert means that a controlled cut is no longer necessary.

A relieved Waywayseecappo Chief Mel Wabash said this is best case scenario: water is going through the culvert and the embankment is holding up.

He wished the federal government had supplied sandbags and resources earlier, but said the community did the best it could with what it had.

Evacuees could be allowed back possibly by the end of Wednesday or on Thursday. Council will meet Wednesday to decide.

The water through the culvert is expected to reach Birtle at about noon Wednesday, the provincial government said.

That community is solidly protected with barricades of sand, earth and aqua tubes.

Ron Bell, the emergency measures public information manager for both the town and the Rural Municipality of Birtle, said the floodproofing will be "more than enough."

"We'll breathe a sigh of relief when the water starts going down and hopefully leaves no damage behind it," he said.

"There's still going to be a considerable amount of work. The clean up will be extensive."