Midwest flooding kills 2 with more rain possible; Minnesota's Rapidan Dam partially collapses

NORTH SIOUX CITY, S.D. -- Floodwaters breached levees in Iowa on Tuesday, creating dangerous conditions that prompted evacuations as the deluged Midwest faced another round of severe storms forecast for later in the day.

A vast swath of lands from eastern Nebraska and South Dakota to Iowa and Minnesota has been under siege from flooding from torrential rains since last week, while also being hit with a scorching heat wave. Up to 18 inches (46 centimeters) of rain have fallen in some areas, and some rivers rose to record levels. Hundreds of people were rescued, homes were damaged and at least two people died.

The sheriff's office in Monona County, near the Nebraska border, said the Little Sioux River breached levees in several areas. In neighboring Woodbury County, the sheriff's office posted drone video on Facebook showing the river overflowing the levee and flooding land in rural Smithland. No injuries were immediately reported.

Patrick Prorok, emergency management coordinator in Monona County, described waking people at about 4 a.m. in Rodney, a town of about 45 people, to recommend evacuation. Later Tuesday morning, the water hadn't yet washed into the community.

"People up the hill are saying it is coming our way," Prorok said.

As new areas were flooding Tuesday, some cities and towns were cleaning up after the waters receded while others downstream were piling sandbags and taking other measures to protect against the oncoming swelled currents. Some normal, unassuming tributaries ballooned into rushing rivers, damaging homes, buildings and bridges.

"Normally, this river is barely a trickle," 71-year-old Hank Howley said as she watched the Big Sioux's waters gush over a broken and partially sunken rail bridge in North Sioux City, South Dakota, on Monday. "Really, you could just walk across it most days."

In a residential development along McCook Lake in North Sioux City, the devastation became clear Tuesday as floodwaters began to recede from Monday, exposing collapsed streets, utility poles and trees. Some homes had been washed off their foundations.

"Currently, there is no water, sewer, gas or electrical service in this area," Union County Emergency Management said in a Facebook post.

President Joe Biden approved a major disaster declaration for affected counties in Iowa on Monday, a move that paves the way for federal aid to be granted.

To the south in Sioux City and Woodbury County, Iowa, officials responded to residents' complaints that they had received little warning of the flooding and its severity. Sioux City Fire Marshal Mark Aesoph said at a news conference Tuesday that rivers crested higher than predicted.

"Even if we would have known about this two weeks ago, there was nothing we could do at this point. We cannot extend the entire length of our levee," Sioux City Fire Marshal Mark Aesoph said. "It's impossible."

Water had spilled over the Big Sioux River levee, and Aesoph estimated hundreds of homes likely have some internal water damage.

Officials in Woodbury County said around a dozen bridges over the Little Sioux River had been topped by flood water, and each would need to be inspected to see if they can reopen to traffic.

Further to the east in Humboldt, Iowa, a record crest of 16.5 feet was expected Wednesday at the west fork of the Des Moines River. Amid high temperatures and humidity, nearly 68,000 sandbags have been laid, according to county emergency manager Kyle Bissell.

Bissell told reporters Tuesday that there was no water on the streets yet, but flooding had begun in some backyards and was reaching up to foundations. Humboldt is home to nearly 5,000 residents.

More severe weather was forecast to move into the region Tuesday, potentially bringing large hail, damaging winds and even a brief tornado or two in parts of western Iowa and eastern Nebraska, according to the National Weather Service. Showers and storms were also possible in parts of South Dakota and Minnesota, the agency said.

In Michigan, more than 150,000 homes and businesses were without power Tuesday morning after severe thunderstorms barreled through, less than a week after storms left thousands in the dark for days in suburban Detroit.

The weather service also predicted more than two dozen points of major flooding in southern Minnesota, eastern South Dakota and northern Iowa, and flood warnings are expected to continue into the week.

Many streams, especially with additional rainfall, may not crest until later this week as the floodwaters slowly drain down a web of rivers to the Missouri and Mississippi. The Missouri will crest at Omaha on Thursday, said Kevin Low, a weather service hydrologist.

The heavy rains were blamed in the deaths of at least two people. On Saturday, an Illinois man died while trying to drive around a barricade in Spencer, Iowa. The Little Sioux River swept his truck away, the Clay County Sheriff's Office said. Officials recovered his body Monday. Another person died in South Dakota, Gov. Kristi Noem said without providing details.

North of Des Moines, Iowa, the lake above the Saylorville Dam was absorbing river surge and expected to largely protect the metro area from flooding, according to the Polk County Emergency Management Agency. The U.S. Army Corps of Engineers projected Tuesday that water levels at Saylorville Lake will rise by more than 30 feet (9 meters) by the Fourth of July.

Outside Mankato, Minnesota, the local sheriff's office said Monday that there was a "partial failure" of the western support structure for the Rapidan Dam on the Blue Earth River after the dam became plugged with debris. Flowing water eroded the western bank, rushed around the dam and washed out an electrical substation, causing about 600 power outages.

Eric Weller, emergency management director for the Blue Earth County sheriff, said the bank would likely erode more, but he didn't expect the concrete dam itself to fail. The two homes downstream were evacuated.

A 2019 Associated Press investigation into dams across the country found that the Rapidan Dam was in fair condition and there likely would be loss of property if it failed. A pair of 2021 studies said repairs would cost upward of $15 million and removal more than $80 million.

Collins reported from Hartford, Connecticut, and Beck reported from Omaha, Nebraska. Associated Press writer Rick Callahan in Indianapolis contributed to this report.