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Flooding in the Midwest increases as heat continues
Flooding in the Midwest increases as heat continues

Flooding that spread across parts of Iowa, South Dakota and Minnesota last weekend is expected to worsen Monday and Tuesday as rivers continue to rise, with forecasters warning that any additional rain from possible thunderstorms could prolong or increase the flood threat.

The flooding is the result of torrential rains that have fallen in parts of the upper Mississippi basin since Thursday, bringing widespread rainfall of between 10 and 18 inches (25 to 45 centimeters), said Todd Heitkamp, ​​a meteorologist with the National Weather Service’s weather service in Sioux Falls, South Dakota. Soils were already saturated by months of wetter-than-average conditions before storms fueled by intense Gulf of Mexico moisture lingered over the region Thursday into Saturday.

That caused rainwater to flow into streams and rivers, overflowing levees in some areas, Heitkamp said. Meteorologists expect rivers to peak on Tuesday or Wednesday, with moderate to record flood levels.

Water levels are “well above normal … suggesting that soils are still moist but have limited storage capacity for further rainfall,” meteorologists wrote on Monday. “Any additional rainfall will further increase the risk of flooding.”

At the same time, the extreme heat that has been sweeping across the country for a week is expected to protect the region from the rising waters. Temperatures in the Midwest are expected to top 30 degrees, and high humidity is expected to make it feel nearly 43 degrees on Monday. That will create “uncomfortable to dangerous” conditions for those outdoors, the weather service warned.

Heat warnings extended across the entire Mississippi River basin on Monday, from Minnesota and South Dakota to the Gulf Coast.

At least one death is linked to the floods in South Dakota, said Governor Kristi L. Noem (Republican) on Sunday. She did not provide further details.

Flood damage was already significant and included the collapse of a railroad bridge connecting Iowa and South Dakota.

Iowa Republican Gov. Kim Reynolds said the floodwaters had damaged or destroyed more than 1,900 homes in at least 22 counties across the state. After taking the death toll from the air on Saturday, Reynolds said “the devastation is widespread.” She said rivers had risen higher than during the great flood of 1993, which inundated nine states, killed 50 people and caused $15 billion in damage.

A rapid flood destroyed an unknown number of homes in North Sioux City, South Dakota, in about 30 minutes on Sunday evening, the Argus Leader reported.

Sioux Falls, South Dakota, Mayor Paul TenHaken urged residents to conserve water as the flooding has placed unprecedented strain on the city’s sewage system and forced authorities to discharge some of the sewage untreated into the Big Sioux River, the newspaper reported.

“Our wastewater collection and treatment systems remain overwhelmed, but they are back to a point where we believe it is manageable,” Sioux Falls Public Works Department Director Mark Cotter said in a statement.

Flooding caused widespread road closures throughout the region, including a brief closure of a section of Interstate 29.

For two South Dakota communities, Mitchell and Sioux Falls, Thursday and Friday were the wettest two-day periods on record, with 7.7 and 6.49 inches of rainfall recorded over 48 hours, respectively, the weather service said.

Since Monday, rivers throughout the upper Mississippi Valley have been in flooding: the James River, Vermillion River and Big Sioux River in South Dakota, and the Des Moines River and Little Sioux River in southwestern Minnesota and northwestern Iowa, according to data from the National Oceanic and Atmospheric Administration.

The weather service warned that flood warnings were in effect in these areas “until further notice.”

According to meteorologists, isolated thunderstorms are possible on Tuesday afternoon. The greatest probability of heavy rain is expected during the night from Thursday to Friday.

“If it rains any more, it will be a punch in the stomach,” said Heitkamp.

By Liam