Updated

MINOT, N.D. -- Watching the Souris River creep over roads and into neighborhoods has amounted to slow torture for North Dakota's fourth-largest city. In the next two days, Minot officials expect the waterway to roar.

The U.S. Army Corps of Engineers on Thursday again accelerated water releases from the upstream Lake Darling dam. Officials said the move could raise the river up to 3 feet higher than earlier projections -- or a whopping 6 1/2 feet above the record set more than a century ago -- in a community where floodwaters already have reached several homes' first floors.

"The water is coming in deeper and faster than was expected," North Dakota Gov. Jack Dalrymple said.

Indeed, in just four days, the predicted release of water from the dam more than doubled -- from 11,000 cubic feet per second to 29,000. National Weather Service hydrologist Steve Buan laid the blame on 4 to 6 inches of rain that fell last week in largely rural -- and saturated -- areas to the north.

"The short answer is, yes, it was from rain," Buan said.

With peak water levels expected Saturday or Sunday, Minot officials said they have done everything they can to protect critical infrastructure. Mayor Curt Zimbelman said dikes have been raised as much as possible around the city's sewer lift station and can't be raised any higher. The city was confident the water treatment plant was protected.

"We need to hope that they hold," Zimbelman said.

Failures there would worsen a desperate situation in Minot, where as many as 10,000 people -- about a fourth of the city's population -- were ordered to evacuate Wednesday.

The city slightly expanded the evacuation zone on Thursday to add about 400 people in the river valley, but that notice was voluntary. Several hours after the expanded zone was announced, officials said damage to those homes might be no more than water in basements.

In Burlington, a town of about 1,000 people a few miles upstream on the confluence of the Souris and Des Lacs rivers, city officials abandoned sandbagging as hopeless. About a third of 320 houses are expected to be lost in the town that was founded in 1883 and is the oldest in Ward County.

"We're no longer able to save the city," Burlington Mayor Jerome Gruenberg said Thursday.

Burlington officials instead sent people to help with a frenzied labor around Minot, a town best known for its Air Force base but also an important agricultural center and home to many laborers drawn to the oil boom in western North Dakota.

Heavy equipment hauled dirt and clay to raise dikes wherever possible -- an effort Zimbelman said would continue until rising water made it impossible. Workers and National Guard members were the only people to be seen in evacuated areas.

Fast-flowing water had overtopped dikes in some places and risen to the first level on several homes. A trailer park was under water. In one area, an old Chevy was half-submerged.

Near the water treatment plant, water had risen above a bridge deck; orange barricades blocked any traffic at either end. Loose clothes, beer cans, dark trash bags, a tire and other assorted trash could be seen floating in the Souris, cast off by departing residents.

Broadway Bridge, on a major north-south artery, was closed around midday and officials fretted over the possible closure of other bridges that would effectively cut the city in two. Two bridges remained open.

Kathy Sivertson, 52, who lives a block outside the initial evacuation zone, was opting to ignore the recommendation for expanded evacuations. She spent part of Thursday moving her belongings out of her basement but said she'd stay in her house until "they kick me out."

Meanwhile, Leon Delker, 55, who lives nine blocks from the river, brought in a survey crew that estimated the water would go 3 feet up on his front door. He planned to clear out everything but the American flag in front of his home and "stay out until this thing is over."

Some residents took refuge on the Souris River Golf Course, where longtime pro Steve Kottsick, 59, pieced together a makeshift 8-hole layout on the flooded course. More than 30 people took their swings on Thursday.

"People are a little down and out," Kottsick said. "Hopefully it helps them maintain some sense of normality."

The city's other 18-hole golf course, the Minot Country Club, lost its clubhouse Thursday.