The same system that brought devastating tornadoes to Pilger, Nebraska last Monday and Wessington Springs, South Dakota Wednesday night, has doused parts of South Dakota, Iowa, Minnesota, Wisconsin, Nebraska and Illinois leading to historic flooding in some areas.

After a week of heavy rains and rising waters, the floods that have developed in the Midwest have become deadly.

Over 7 inches of rain fell Friday night and early Saturday on parts of Omaha, causing some flooding of low-lying streets and contributing to the death of a Bellevue man swept away by floodwaters after he drove into a rain-swollen ditch.

Authorities said they recovered the body of David Farr, 29, Saturday morning near a drainage ditch just south of Highway 370. Police and rescue workers were called to the area Friday night by witnesses who said Farr was able to get out of the car, but was soon pulled underwater and didn't resurface.

(MORE: Flash Flooding Strikes Omaha)

Firefighters were unable to enter the water because the current was too strong.

The incident happened as heavy rains pummeled the area Friday night, forcing the postponement of a College World Series game and adding to concerns of flooding along the Missouri River. The National Weather Service has issued a flood warning for parts of Nebraska and Iowa along the river, swollen from heavy rains in states north of Nebraska.

A spotter on the border between Omaha and La Vista, Nebraska, measured 7.75 inches of rainfall. Friday night's storms also brought high winds and lightning and led to power outages across the area. Omaha Public Power District told the Omaha World-Herald that 2,978 customers in Douglas and Sarpy counties were without power early Saturday morning, down from about 10,000 customers at the height of the storms, the utility said.

Following the rain, the Missouri River had reached 27.2 feet at Omaha by Saturday morning, the National Weather Service said. It's forecast to rise to flood stage at 29 feet around 9 a.m. Sunday. Flooding is expected in low-lying parks near the river, including in NP Dodge and Freedom parks in Omaha, Playland Park in Council Bluffs, Iowa, and Fontenelle Forest and Haworth Park in Bellevue.

"As typical for summer, clusters of thunderstorms with locally heavy rain are possible through the weekend in parts of the waterlogged Upper Midwest and Plains," said weather.com senior meteorologist Jon Erdman.

Luckily, in South Dakota, the Big Sioux River crested earlier and at a lower level than expected early Friday, prompting 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 city. The road, which Lt. Gov. Matt Michels said remained dry while closed, reopened Friday afternoon. But some buildings, farmland and roads remain flooded, Michels said.

"Do not drive on a road with water. It may not be there," he said.

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.

Still, days of flooding in Minnesota were too much for the land in one area, as a mudslide along the Mississippi River led to a partial road closure and the evacuation of some employees at a Minneapolis hospital.

(MORE: Pilger, In Their Own Words | PHOTOS: Tornado Outbreak)

Deputy Fire Chief Todd White tells the Star Tribune that the slide occurred around 7 p.m., sending a 100-yard swath of the bluff onto the road and river below. He says about 6 to 8 feet of mud were left on the West River Parkway, which was partially closed. No one was injured.

A statement from the Fire Department says crews determined the University of Minnesota Medical Center was not affected.

The Pioneer Press reports 20 administrative employees of the hospital were evacuated as a precaution. Patients were not affected.

The mudslide comes after torrential rain and flash flooding in the area Thursday.

Over six inches of rain in eight hours fell on the south side of the Twin Cities metro Thursday morning, sending Minnehaha Creek out of its banks. Nearby homeowners were scurrying to sandbag to protect their homes against the rising creek.

Minnesota officials toured water-logged areas of the state Friday, saying the severity and breadth of flooding make a federal disaster request a near certainty and a special legislative session a possibility.

Farm fields are under water, roads have been washed out, dams have failed and water has infiltrated homes from the far north to the far south of Minnesota. 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 before boarding a plane to southern Minnesota along with U.S. Sens. Al Franken and Amy Klobuchar. Dayton has already declared a state of emergency in nearly half of Minnesota's counties.

Damage assessments already total in the millions even before surveying can start in many places soaked by downpours over the past week. Some lakes and rivers swelled to record levels, with others not expected to crest for days, if not weeks.

Thursday was the record wettest June day in the Twin Cities, as 4.13 inches fell on Thursday. This topped the old record from June 29, 1877 (3.48 inches). Also, through June 19, it has been the record wettest year-to-date in the Twin Cities, with just over 25 inches of precipitation (rain, melted snow equivalent). This is about 13 inches wetter than average for the year, so far.

(MORE: Here's How You Can Help the Victims of the Nebraska Tornadoes)

Gov. Daugaard declared a state of emergency for South Dakota on Tuesday. Daugaard also ordered the opening of the State Emergency Operations Center to monitor the effects of the torrential rains and coordinate the state's response. The Red Cross also opened an emergency shelter to help people who have been evacuated or are can't reach their homes because of the flooding, KTIV reports. 

Sioux Falls, South Dakota obliterated its previous wettest month on record, 9.42 inches in May 1898, taking only half the month to do it. Through June 21, 13.39 inches of rain had soaked Sioux Falls, which is over half the average yearly precipitation of 26.38 inches. Sioux City, Iowa, broke its wettest month on record Friday, and by Sunday, Sioux City's total had reached 13.25 inches, well above the old single-month record of 11.78 inches in May 1903.

In both cities, the June rainfall totals have eclipsed the average rain for an entire year from Jan. 1 through the summer solstice.

Floodwaters blocked many of the roads connecting South Dakota and Iowa between Sioux Falls and Sioux City.

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 north-south corridor reopened Friday afternoon.

"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.

Along the South Dakota-Iowa border, the town of Canton, South Dakota, was hit hard by flooding earlier this week, and many homes were destroyed.

"I have nothing left. It's all gone," said Dale Larson, Canton resident, in an Argus Leader report on Tuesday.

Within a 24-hour time span between Monday morning and Tuesday morning, 8.43 inches of rain was measured in Canton, about 20 miles southeast of Sioux Falls. According to the National Weather Service, this was the third highest 24-hour precipitation total in state history, narrowly missing the all-time record of 8.74 inches on May 6, 2007 in Groton. 

The flooding stretched over the border into western Iowa, where Rock Rapids and Rock Valley have been partially evacuated. In Rock Rapids, about 60 homes have had water waist deep or higher in them, Mayor Jason Chase said, and many have shifted from their foundations or have damaged basement walls.

"This is the worst I've seen and I've been here since 1997," he said. Several families remain in a Red Cross shelter, Chase said.

Gov. Terry Branstad and Iowa Homeland Security and Emergency Management Department Director Mark Schouten surveyed damage in Rock Rapids and Rock Valley on Wednesday.

Rock Valley, about 20 miles southwest of Rock Rapids, requested pumps and sandbagging materials from the state after a levee broke on Tuesday night. The river is receding, but a local shelter still is available for residents needing to leave their homes.

The Big Sioux River set record flood levels at Hawarden and Akron where it peaked Tuesday. A levee also was breached in Akron, causing several residents to be evacuated late Tuesday night and early Wednesday. The city pumped out floodwaters to protect City Hall and other buildings.

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.

Information from the Associated Press was used in this report.