SALMON, Idaho Authorities pressed a mandatory evacuation on Wednesday in flood-hit parts of Minot, North Dakota, and South Dakota's governor urged residents to evacuate parts of the capital ahead of rising flows from the swollen Missouri River.
Police and National Guard soldiers went door-to-door in Minot urging up to 12,000 residents to evacuate as officials cut natural gas service to neighborhoods affected by rising waters along the Souris River, a Red River tributary.
Flooding on the Souris has eclipsed records set in damaging floods in 1976 and 1969 and forced Amtrak to suspend service on its Empire Builder line west of St. Paul due to track closings and damage to its Minot station.
Volunteers, contractors and National Guard soldiers and airmen were racing on Wednesday to extend and raise levees in North and South Dakota cities including both state capitals to hold back the rising Missouri River.
Heavy rains and a deep melting snowpack from a snowy winter have led to historic water levels in the Missouri River basin and nearby river systems from Idaho to North Dakota and down through South Dakota.
Six reservoirs on the Upper Missouri River are straining at or near capacity, forcing the U.S. Army Corps of Engineers to release water that will push the river several feet above already high levels.
The Missouri River basin forms the northwest bowl of the massive Mississippi River system that stretches from the Rockies to western New York in the north and funnels water down through Louisiana to the Gulf of Mexico.
The Corps held back on releasing flows to take some of the edge off what has already been record Mississippi River flooding this year in some areas of the mid-South. Current releases will take nearly two weeks to reach the Mississippi River near St. Louis. Mississippi flood stages are expected to be extended a few weeks by the Missouri flows, but not raised.
DAMS, LEVEES, SANDBAGS STRAINED
"It is a lot of water to move," said Eric Stasch, operations manager for the Corps at the Oahe Dam above Pierre.
Above the North Dakota capital at Bismarck and nearby Mandan, Bismarck officials said they were far short of a goal of amassing sandbags to protect the town as the Corps opened Garrison Dam spillways on the Missouri for the first time.
The Corps does not expect to open a spillway from the Oahe dam above Pierre, the South Dakota capital, but was shaping the area with bulldozers to stop water from flowing down a highway if the spillway must be opened.
In South Dakota, progress was seen in flood preparations. Levees in Pierre and Fort Pierre were expected to reach at least base levels by late Thursday as planned, officials said.
Officials believe flooding could displace up to 2,000 Pierre residents and that more than 800 of 1,100 residences in Dakota Dunes near the Iowa border may sustain flooding.
South Dakota Governor Dennis Daugaard called for Pierre and Fort Pierre residents in areas threatened by flooding to leave by 8 p.m. Thursday. The order was not mandatory. But officials were set to go door-to-door starting on Wednesday, he said.
Daugaard also said Dakota Dunes residents should have possessions moved and property secured by late Thursday for a possible evacuation that he may make mandatory.
Two helicopters helped place sandbags in Dakota Dunes and a major community road was closed for hours to give construction crews better access to levees, Daugaard said.
"We are making progress, but it is a tall order," he said.
The Corps has started gradually releasing water from the reservoirs, but is expected to step up the pace quickly after the weekend to reach maximum flows by mid June, making room for additional water flowing in from the rains and thaw.
Farther downstream from Dakota Dunes, residents in Nebraska, Iowa and Missouri braced for widespread flooding that could extend well into the summer, officials said.
In Montana, flooding of the Missouri River and its tributaries has forced the evacuation of 500 people. Residents of Roundup, a central Montana town of 2,000, were warned to get set to evacuate as a precaution as emergency workers struggled to repair a breached levee on the Musselshell River nearby.
"We don't know what to expect next," said Rich Borner, a volunteer with the Roundup area's emergency services agency.
The American Red Cross of Montana on Wednesday reported 1,844 overnight stays at Red Cross shelters in the state since flooding began nearly a fortnight ago.
The Red Cross sent a psychologist to help counsel the more than 200 people at a Billings shelter. Many of the displaced are from the Crow Indian Reservation in southeastern Montana inundated by the Bighorn and Little Bighorn rivers.
(Reporting by Laura Zuckerman in Salmon, Idaho; Writing by David Bailey; Editing by Greg McCune and Peter Bohan)