By David Bailey
MINNEAPOLIS (Reuters) - The levees protecting up to a quarter of Minot, North Dakota, are expected to be breached by rising waters from the Souris River later on Wednesday, North Dakota Governor Jack Dalrymple said.
Minot officials have ordered a mandatory evacuation for up to 12,000 residents of the city, North Dakota's fourth largest, by 6 p.m. on Wednesday. Some areas just outside and north of Minot were ordered evacuated by noon Wednesday.
Heavy rains over the past six weeks have swelled Canadian reservoirs in the Souris River basin, forcing unprecedented water releases. In turn, U.S. officials must release water from the Lake Darling Dam above Minot at a rate more than double what the recently fortified protections can bear.
The massive flooding on the Souris River, which flows into the Red River basin, struck as residents from Montana through Missouri battle Missouri River flows that threaten the North Dakota capital of Bismarck, the South Dakota capital of Pierre and other communities for hundreds of miles downstream.
"I never thought we could possibly have anything even coming close to what is happening in Bismarck-Mandan this year, but the fact of the matter is, the levees in Minot are expected to breach later today," Dalrymple told reporters in a briefing in Bismarck.
"There will be a lot of water in the city," he said.
Officials also have warned residents that they may need to evacuate before the deadlines if water runs over the top of the levees before then and urged people to map out a direct route to head for higher ground if warning sirens sound.
The U.S. Army Corps of Engineers plans to step up releases from the Lake Darling Dam and to 15,000 cubic feet per second on Thursday. Flood defenses in Minot were rated to perhaps 9,500 cubic feet per second, officials have said.
The Corps expects peak releases to reach about 20,000 cubic feet per second by late June and hold there for up to six days before a gradual reduction back to below 8,000 cubic feet per second over five days.
Amtrak suspended Empire Builder service Tuesday in part of Minnesota, North Dakota and eastern Montana due to flooding.
Heavy rains added to woes across the Missouri River basin from Montana through Missouri earlier this week and forced federal officials to adjust planned water release rates from some of its six reservoirs on the Upper Missouri River.
The Corps plans to reduce some releases to allow flows from tributaries to pass, but will increase the expected maximum at the key Gavins Point Dam on the South Dakota-Nebraska border. Rates already are roughly double the previous record.
The Missouri River runs freely from Gavins Point for more than 800 miles to the Mississippi River near St. Louis, making the releases from the dam a focus for downstream residents.
The Corps plans to increase water releases at Gavins Point to 155,000 cubic feet per second on Wednesday and to 160,000 on Thursday. It plans to hold peak releases at least through mid-August.
(Additional reporting by Kevin Murphy in Kansas City, Missouri; Editing by Jerry Norton)