A slow-motion disaster is worsening in the central US. The spring thaw and more recent heavy downpours from repeated thunderstorms have broken both flood and rainfall records, many decades old.

The middle section of the country has been experiencing major flooding since mid-March, especially along the Missouri, Arkansas, and Mississippi Rivers. Towns along the Mississippi have been experiencing the longest stretch of major flooding in nearly a century.

The city of Morrilton, that sits on a bend in the Arkansas River has not seen water levels this high since the Great Flood of 1927, according to Weather Underground.

For the first time, the US Army Corps has had to fully open all gates of the Ozark Lock and Dam near the town of Ozark, Arkansas, to allow the swollen river to move freely through the structure.

The Arkansas River has also reached its highest level since 1943 in Muskogee, Oklahoma, because of heavy rain upstream in northern Oklahoma and southern Kansas.

The Missouri River is at its highest level since 1995 in Jefferson City, Missouri. Next week, as the flood moves downstream, St Louis will see the second major crest of the Mississippi River in just under a month. This crest is expected to be higher than that of the Mississippi River flood of 1973 and come close to the Great Flood of 1993.

“The current flood fight is historic and unprecedented,” said a US Army Corps statement. Monday was the 214th day of the flood fight and “is expected to surpass the 1973 event (225 days) as the longest flood fight,” the statement said.

The persistent jet stream pattern in the skies above the US is finally changing, reducing the risk of repetitive downpours. Big thunderstorms will still build and will bring flash flooding so the runoff alone may continue to aggravate this historic flood season.