The swollen Souris River whose waters deluged North Dakota's fourth-largest city of Minot, was expected to crest early on Sunday, with storms threatening to complicate efforts to contain the biggest flood in area history.
Local and federal officials worked feverishly to reinforce levees, protect the city's key infrastructure and care for thousands of residents forced to flee their submerged homes.
By Saturday evening, the Souris, which flows from Canada southeast into North Dakota, was at least 3.5 feet above the 130-year-old record it shattered on Friday.
Under current conditions, the river is expected to crest by Sunday morning at 3.8 feet above that record, according to the National Weather Service.
"We will continue to be at this highest level for the next several days," said Minot Mayor Curt Zimbelman, adding that the possibility of rain could complicate containment efforts.
"There is a cluster of thunderstorms that are pretty close to Minot now. It looks like a couple of inches of rain could impact some of the areas with flooding," said Rich Thompson, a lead forecaster at the National Weather Service's Storm Prediction Center.
There have been no reported deaths or injuries.
"There is still a tremendous amount of water and even when this crest has passed, there will be months of a recovery effort," U.S. Army Corps of Engineers spokesman
Jeffrey DeZellar said.
"When the water goes down it relieves pressure on emergency levees, but there has been so much damage done to the community that there is going to be a tremendous recovery effort," DeZellar said.
Authorities were also trying to stop a walking bridge that collapsed in the middle of the river from crashing into a downriver dam, a Minot Fire Department official said. The bridge had not moved as of Saturday evening.
Floodwaters have all but swallowed more than 3,000 Minot-area homes, according to North Dakota Department of Emergency Services spokeswoman Cecily Fong.
Officials' attention has turned to displaced residents, more than 12,000 of whom heeded mandatory evacuation calls.
Some moved in with friends or family, but more than 250 people were holed up in Red Cross shelters at a city auditorium and Minot State University or at the Minot Air Force Base.
More evacuees were expected from the towns of Turtle Lake, Velva and Sawyer, among others, according to Allan McGeough, executive director of the mid-Dakota chapter of the Red Cross.
In Sawyer, about 16 miles southeast of Minot, 400 residents were told to evacuate after river water rushed through a downtown roadway, and as many as 300 people in Velva will require shelter, McGeough said.
Flood warnings have been issued from Burlington, northwest of Minot, through Logan and Sawyer to the southeast.
The massive flooding in Minot has overshadowed temporarily the widening deluge along the Missouri River that threatens cities from Montana through Missouri.
Federal officials have pushed record water releases from six reservoirs along the Upper Missouri River that are near capacity because of a deep melting snowpack and heavy rains.
Those reservoirs have little capacity for additional rain, and record releases are expected to continue through August, causing widespread flooding in Nebraska, Iowa, and Missouri.
Heavy rains across the Souris River Basin left Canadian reservoirs over capacity. Water rushing down from Canada has forced U.S. officials to make record-large releases from the Lake Darling Dam above Minot and other communities.