In the meantime, federal hydrologists are keeping a close eye on two flood crests – one working its way down the Mississippi and one on the Ohio River, which empties into the Mississippi at Cairo, Ill.
The Mississippi's largely snow-melt driven crest is expected to pass Cairo first, followed closely by the crest from the Ohio. The two are expected to move south in tandem along the lower Mississippi.
Over the next two days, this one-two punch is expected to bring record or near-record flood levels to a stretch of river from Smithland, Ky., on the Ohio to New Madrid, Mo., on the Mississippi, according to Noreen Schwein, deputy for hydrological services at the National Weather Service's Central Region Headquarters in Kansas City, Mo.
Officials with the US Army Corps of Engineers were sufficiently concerned about this pending aquatic onslaught that they were considering blasting a hole in a levee along the Mississippi just south of its junction with the Ohio. But they reportedly put off a decision after Missouri's attorney general went to court to block the move, arguing that some 130,000 acres of farmland would become inundated.
The challenge presented by a pair of closely-spaced, slow-moving crests is that they tend to back water up behind them, prolonging the time that levees are under stress and that communities upstream continue to face flood conditions, says the National Weather Service's Schwein.