Historic floods wash away homes and memories in Iowa and Minnesota

Very slowly, then all at once, a house overlooking the Blue Earth River and Rapidan Dam in Minnesota plunged into the waters below Wednesday, as surging floodwaters caused devastation across the Midwest.

A day earlier, homeowner Jenny Barnes spoke to NBC News on a bench near the property — a spot that has now also washed away.

The Barnes' nearby cafe, the Rapidan Dam Store, popular for its pies and ice cream, has survived. "We don’t know what will happen. Minute by minute has been playing out right in front of our eyes and it’s hard to experience," a post on the store's Facebook page said on Wednesday, adding that the family-run establishment "has not sold its last burger or sold its last slice of pie."

It's just one story among many of homes and businesses being lost in the region. In Sioux City, Iowa, people with houses along the river began returning to their homes Wednesday to find scenes of destruction.

At least 20 rivers are still in a major flood stage, mostly across southern Minnesota and northwest Iowa.

And there could be yet more severe weather on the way, with the chance of storms in the upper-middle Mississippi Valley on Thursday night and into Friday. Some 6 million people are at risk of storms in the Rockies and Northern/Central Plains.

The heaviest rain, about 1 to 2 inches, is due to land south of the affected rivers — but even a small amount could cause more flooding.

There is a slight chance of excessive rain, the National Weather Service said in a forecast, which would increase the risk of flash flooding.

High water levels at the Rapidan Dam on the Blue Earth River in Mankato, Minn., on Monday. Ben Brewer / Bloomberg via Getty Images

Farmland in the region has been hit hard by the floods. The U.S. Department of Agriculture said Wednesday that the Upper Midwest received twice the normal amount of rain last week, with 9 inches falling in places.

Brad Dehn, a crop farmer with over 1,300 acres in Wright County, Minnesota, said his soybeans are stunted and his corn is shorter than normal.

"The roots are shallow. They haven't gone down deep yet," Dehn said. "That’s not to say it can’t get better, but it’s got its challenges going forward," he told NBC affiliate KARE of Minneapolis.

As people affected by floods begin to rebuild their lives, officials are warning that scammers may take advantage of victims.

Iowa's statewide auditor, Rob Sand, said Wednesday that fraudsters posing as legitimate contractors could disappear without finishing or even starting repair work.

"They literally go around the country following storms and try to take advantage of people who are in their worst situation in their life," he told KARE. "And we’ve got to watch out for that."

The Home Builders Association of Greater Siouxland warned people against paying the full price of any work up front.

Storms also rocked the Northeast on Wednesday, knocking out power for more than 250,000 energy customers across the region as of Thursday morning. New York City was hit by severe storms that brought lightning, hail and strong winds to the metro area, downing trees and power lines.

Some 10 million people will be at risk of severe storms on Friday across the Central Plains and Midwest, with large hail and high winds possible for western Nebraska and parts of Kansas. The tornado threat will be highest in northeast Kansas and northwest Missouri.

At least 21 million people in Southern states were under heat alerts for Friday. Areas of Texas, Oklahoma and South Carolina could all reach over 100 degrees on the heat index, a measure of how hot it actually feels with humidity.

Patrick Smith is a London-based editor and reporter for NBC News Digital.