By Geoff Davidian
MINOT, North Dakota (Reuters) - The biggest flood in area history swallowed large swatches of North Dakota's fourth largest city on Saturday, as authorities worked to reinforce levees, protect the city's key infrastructure and care for residents forced to flee their submerged homes.
The Souris River, which flows from Canada southeast into North Dakota, was at least 3.5 feet above the 130-year-old record it shattered on Friday. The river was expected to crest on Sunday to approximately 5 feet over that record and remain there for several days, according to U.S. Army Corps of Engineers spokesman Jeffrey DeZellar.
"The historic flood is hitting. We are working to stem the tide," DeZellar said. "We are mostly working to reinforce emergency levees in Minot and downstream communities. It is very challenging construction."
Authorities were also trying to stop a bridge that collapsed in the middle of the river from crashing into a downriver dam, a Minot Fire Department official said.
Local and federal officials have moved thousands of tons of dirt to construct levees and dikes and laid sandbags to rein in the waters, DeZellar said.
Some tactics have failed, however, and the floodwaters have all but swallowed more than 3,000 Minot-area homes, according to North Dakota Department of Emergency Services spokeswoman Cecily Fong.
"There is so much water, it's up to and over people's rooftops," Fong said.
Officials' attention has turned to displaced Minot-area residents, more than 12,000 of whom heeded the mandatory evacuation call on Wednesday, Fong said.
Some have moved in with friends or family but more than 300 residents were holed up in Red Cross shelters at a city auditorium and Minot State University or at the Minot Air Force Base. Those numbers were expected to increase.
There have been no reported deaths or injuries, DeZellar said.
A second evacuation has been issued in Sawyer, a town of about 400 people 16 miles southeast of Minot, where local and federal officials are working to construct an emergency levee to protect the city from inundation.
"There was flooding down a roadway that started to inundate portions of the town," DeZellar said, adding that the gushing waters complicated construction efforts.
Flood warnings have been issued throughout the region 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.
(Writing by Eric Johnson; Editing by Ellen Wulfhorst)