Flooding struck parts of the Plains and Midwest on March 15 and 16 in the wake of the “bomb cyclone.” (Video: Patrick Martin, Melissa Macaya, Adriana Usero/The Washington Post)

Across the Midwest, the “historic” flooding that has killed at least two people and prompted leaders to declare states of emergency continued through the weekend, forcing more residents to flee their homes.

The surging water, fueled by a powerful winter storm, overwhelmed infrastructure, threatened a nuclear power plant and cut off access to some towns and cities. In Nebraska, which has seen some of the most significant damage, Gov. Pete Ricketts (R) said the impact of the “devastating flooding . . . could last for quite some time.”

On Sunday, state officials confirmed two flood-related deaths and said two other men have been missing for days.

News of the fatalities came as residents in neighboring Iowa were driven from their homes as the Missouri River breached and broke levees. In the southwest corner of the state, the river rose to just over 30 feet, well beyond the previous record, the Associated Press reported.

“It’s flowing fast and it’s open country — there’s nothing there to slow it down,” Mike Crecelius, director of emergency management in Fremont County, Iowa, told AP.

James Wilke, a 50-year-old Columbus, Neb., farmer, was killed on Thursday when a bridge collapsed as he used a tractor to try to reach stranded drivers, AP reported. The next day, Aleido Rojas Galan, a 52-year-old resident of Norfolk, Neb., was swept away in floodwaters in southwest Iowa.

The National Weather Service warned that parts of Minnesota, Wisconsin and South Dakota — as well as Nebraska and Iowa — could still face flooding this week.

Many places are underwater, from Nebraska to Wisconsin, as major flooding engulfs the region

A “bomb cyclone” — a hurricane-like winter storm — battered the region with strong winds and heavy rainfall. The resulting flooding was particularly intense, because the heavy rain fell on snow that had not melted yet, said Brian Barjenbruch, the science and operations officer for the Weather Service in Omaha.

“And the ground was completely frozen,” he said in an interview. “It’s almost like all of this rain was falling, melting snow and every last drop had to run off.”

Barjenbruch said the results have been incredibly damaging in parts of eastern Nebraska and western Iowa.

“It is some of the worst flooding that we’ve seen in many years,” Barjenbruch said of those areas. “In some locations it’s the worst flooding on record on many of these river gauges.”

Even the forecasters themselves were not immune: The National Weather Service in Omaha reported Friday that it had to evacuate its offices because of rising waters.

Offutt Air Force Base reported on Sunday that one third of the base was underwater. Thirty buildings at the facility just outside Omaha were flooded with up to eight feet of water, the Omaha World-Herald reported, and about 3,000 feet of runway was submerged. The headquarters of the U.S. Strategic Command, which sits on higher elevation, was not affected.

Along with Ricketts, governors in Wisconsin and South Dakota declared emergencies, while Iowa’s governor issued a wave of disaster proclamations. South Dakota Gov. Kristi L. Noem (R) said she signed an emergency declaration to free up more state money for people affected by the storm and the flooding.

“The storms this week have been extremely difficult for many of our communities,” Noem said in a statement. “This has been a statewide emergency with people impacted by heavy snow, high winds, rain, and freezing rain.”

In his emergency declaration, Wisconsin Gov. Tony Evers (D) said the storm had “moved across the entire state of Wisconsin” between Wednesday and Friday. In its wake, he said, water was “rising swiftly.”

“The warm temperatures and rain the last few days have caused much of the heavy snowpack and ice to melt, resulting in flooding, ice jams, and rivers and creeks to rise,” Evers said in a statement.

In Nebraska, more than 650 residents rushed to shelters while state troopers fanned out for water rescues, officials said.

“Nebraska has experienced historic flooding and extreme weather in nearly every region of the state,” Ricketts posted in a statement on Twitter. He issued a disaster declaration on Tuesday.

President Trump on Friday afternoon said he spoke to Ricketts about the situation.

“The people of Nebraska & across the Midwest, especially the Farmers & Ranchers, are feeling the impacts from severe weather,” he tweeted.

The flooding closed off main routes through parts of the region, said Jennifer Arthur, 44, a bartender at Jack’s Place in Omaha.

“You go a couple of miles . . . you can’t make it very far,” Arthur said. “You just can’t get into town.”

Arthur said Jack’s had additional customers because the water had closed some other bars and restaurants — and the flooding was the main topic of conversation.

“There’s a lot of people impacted that had to get out real fast,” she said. “A lot of people are going to friends’ houses, hotels.”

The Cooper Nuclear Station, a power plant that sits along the swelling Missouri River in southeast Nebraska, may also be forced to close as the water continues to rise, the facility’s officials said. Employees are piling sandbags along the levee that protects the plant and around the building’s doorways, the Omaha World-Herald reported. Officials said a shutdown won’t harm the nuclear reactor.

But flooding has already caused severe damage in some areas, tearing apart pieces of roadways and bridges, authorities said.

“The power of water is really quite impressive,” Barjenbruch said. “When that water moves out of the channel it is normally in, it interacts with roads, bridges in ways it doesn’t normally. When that happens . . . we have roads fail, bridges fail, we’ve even had dams fail in far northeastern Nebraska.”

Barjenbruch added: “The power of water should never be underestimated.”

Forecasters have also warned that, because of significant precipitation during winter and because of what The Washington Post’s Capital Weather Gang called “an active spring storm track through the nation’s midsection,” this flooding in the Midwest may only be the start of a painful flood season.

-- Tim Elfrink contributed to this report

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