Mississippians Told to Expect April Floods

The Mississippi River is starting its spring climb with forecasters predicting a rise of more than a foot a day beginning at midweek.

The result could be another year of flooding in the Vicksburg area.

“Right now, we’re looking at above-normal potential for spring flooding,” said Marty Pope, senior service hydrologist for the National Weather Service in Jackson. “The snow melt up north is over for the most part, so what we have to watch out for now are heavy rains over the Upper Mississippi River and Ohio River valleys.”

The long range forecast by the Lower Mississippi River Forecast Center in Slidell, La., is calling for the city of Cairo, Ill. — where the Mississippi and Ohio rivers converge — to crest at 5.5 feet over the city’s flood stage of 40 feet on March 25.

LMRFC Hydrologist Daniel Pearce tells the Vicksburg Post that the Vicksburg area also likely will be nearing its flood stage of 43 feet by the end of the month.

“It’s hard to predict exactly, but Vicksburg will probably be around 38 to 40 feet in early April or late March,” Pearce said.

While snow melt in Northern states obviously factors into spring river rises farther south, Pope said the river stage at Vicksburg will be more affected by rainfall in the river valleys upstream.

“The snowmelt leaves the soil moist, and if you get a heavy rainfall off that saturated soil it can lead to sharp rises in the river.

“The entire valley is extremely wet right now, and so what we’re going to have to be concerned about are any heavy rains before the river crests. It looks like a fairly decent system will pass over the valley on Sunday. It doesn’t look like anything excessive, but it will certainly add some water to the system,” Pope said.

The Mississippi River topped flood stage at Vicksburg the past two years.

In 2008, the river topped 43 feet on March 29 and crested three weeks later at 50.9 feet. It was the highest river stage recorded at the city in 35 years, dating to 1973 when the river topped out at 51.6 feet. In 2009, the river topped flood stage on May 13 and crested two weeks later at 47.5 feet.

Farmers in the levee-locked Yazoo Backwater Area suffered through back-to-back years of near-record flooding in 2008 and 2009. Flooding in the backwater area usually follows flooding on the river, as the high river stage generally forces the gates of the Steel Bayou Control Structure to close.

Steel Bayou is the lone drainage point for the 4,093 square miles of farmland and forest known as the Yazoo Backwater Area. Its four, 30-foot-wide gates must close when the river stage is higher than the water stage inside the backwater area. With the gates closed, any rainfall over the backwater area is impounded.

Normal water stage for the backwater area is 69 feet, and crops begin going under water at about 86 feet.

In 2008, the gates of the Steele Bayou Control Structure were closed on March 13 and were not able to be reopened for 27 days, at which point the water stage inside the structure was 92.3 feet. The U.S. Army Corps of Engineers estimated a total of 344,000 acres of forest and farmland were flooded.

Last year was worse in the backwater area, with the water stage topping out at 93.7 feet on June 4.