NORTH SIOUX CITY, S.D. (AP) — A swollen river that threatened homes where Iowa, Nebraska and South Dakota meet crested earlier and at a lower level than expected early Friday. Minnesota officials toured water-logged areas of that state, saying the severity and breadth of flooding make a federal disaster request a near certainty.
The less-serious crest of the Big Sioux River prompted crews to start taking down sandbags and other containers blocking a section of Interstate 29 that acted as a temporary levee to protect an at-risk South Dakota city.
The National Weather Service had predicted the river would hit a record high around midday, but later said it crested at Sioux City, Iowa, around midnight a couple of feet below the previous record.
Days of thunderstorms upstream swelled the 420-mile-long river and threatened homes and businesses in the three surrounding states, including up to 400 in a neighborhood of North Sioux City, South Dakota.
Crews built a temporary levee across a section of Interstate 29, forcing motorists to make detours along country roads. National Guard soldiers and South Dakota Transportation workers started dismantling the levee on Friday, removing sandbags and other containers. The governor's office said I-29 should reopen later Friday.
Floodwaters blocked many of the roads connecting South Dakota and Iowa between Sioux Falls and Sioux City.
"Great news," Gary Bogenrief, 65, who lives near McCook Lake, said upon hearing the levee was coming down.
The change in the crest was due to a large amount of water released Tuesday night when a levee failed upstream at Akron, Iowa, said Mike Gillispie, a hydrologist at the National Weather Service in Sioux Falls.
"Enough water went through the levee failure out into agricultural land there that it lowered the amount of water coming through at peak crest at Sioux City," he said.
The river had been expected to crest at Sioux City about a foot above the 108.3-foot record set in 1969. Instead, it peaked at 105.6 feet and began dropping.
As a result, the river in the Sioux City area will stay at a higher level longer than previously predicted, Gillispie said. He expects it to stay above the 99-foot flood stage, the level at which farmland around Sioux City is underwater, into Sunday or Monday.
He said as long as the area doesn't get heavy rain over the next few days, the water should fall back below flood levels. While there is potential for scattered thunderstorms, he doesn't anticipate widespread rain that could send the river significantly higher.
In Minnesota, heavy rains over several days left farm fields are under water and roads washed out. Dams have failed and water has infiltrated homes from the far north to the far south of the state. Four state parks have been fully or partially closed because of high water.
"The damage is really unprecedented and very widespread," Gov. Mark Dayton said.
In Minneapolis, a large section of mud gave way on a cliff near the Mississippi River. The slide occurred not far from a hospital near the University of Minnesota's campus. Minneapolis Assistant Fire Chief Charles Brynteson said the hospital building is set on bedrock and is sound. Two motorists accelerated to safety as the mud and debris were falling.
"They very easily could have been trapped," he said. "It was close."
Downstream, the Omaha Public Power District said it will reduce power as it prepares for rising water on the Missouri River. The district's Fort Calhoun nuclear power plant sits about 20 miles north of Omaha, and was surrounded by water during flooding three years ago.
Pitt reported from Des Moines, Iowa. Associated Press reporter Brian Bakst in St. Paul contributed to this report.
Contact Dirk Lammers at http://www.twitter.com/ddlammers.