Mississippi Delta braces for historic flooding

US authorities yesterday were preparing to open up a major floodgate to ease pressure from the swollen Mississippi River, hoping to save urban centres from historic flooding as rising waters swept south.

Louisiana’s Morganza Spillway could be opened to stop flood waters from washing into major cities, the US Army Corps of Engineers said, aiming to ease the Mississippi’s flow as it heads for the Gulf of Mexico.

The Corps has scheduled an afternoon press conference in Morganza, some 120 km northwest of New Orleans.

“Baton Rouge and New Orleans will flood if we don’t open that spillway,” retired general Russel Honore, best known for leading the military response to the 2005 Hurricane Katrina disaster, warned on CNN.

Opening the spillway would see waters gush over thousands of acres of farmland and rural towns, prompting warnings of flash floods from forecasters and urgent evacuation orders in Louisiana and Mississippi.

The American Red Cross is already readying shelters for thousands of expected evacuees.

But Louisiana Governor Bobby Jindal said people had time to prepare and pack, adding that the Corps had told him the spillway would be opened yesterday, according to the New Orleans Times Picayune newspaper.

“Now is the time to take action. Don’t delay. Don’t hope something will change,” said Jindal, quoted by the New Orleans Times Picayune, adding it would be a slow release of water.

The trigger for the opening, Jindal said, would be when 42,000 cubic metres of water per second was flowing down the Mississippi at Red River Landing – a point that had nearly been reached with the level at 1.423 million cubic feet last Friday.

The river, cresting upstream in Arkansas, is set to eclipse the high water records set in the epochal floods of 1927.

Near its height, the Mississippi town of Vicksburg is expecting a forecasted 17.5-metre-crest on Thursday, topping the 56.2-foot historic crest set 84 years ago this month, National Weather Service data said.

The Mississippi is the third-longest river in North America and its watershed is the fourth-largest in the world, according to the US National Park Service.

According to flood projections from the Corps, a flood as high as 4.57 metres was set to bear down on the small Louisiana community of Butte La Rose when the spillway is opened.

Despairing resident Pierre Watermeyer told CNN, simply: “It’s over with, it’s over with.”

“It’s worse than we thought,” resident Kelli Trimm told the news network as the town scrambled to gather belongings and flee.

“It’s going to take everything, everything we’ve got. It’s scary. It’s going to take out our whole community,” she said.

If the Morganza Spillway is not opened in time, the Corps warned earlier last week, flooding reaching as high as 7.6 metres was expected to soak New Orleans.

The worst floods to hit the central US in more than 70 years have already swallowed up thousands of homes, farms and roads in Illinois, Missouri, Kentucky, Tennessee and Mississippi.