New Orleans Faces Threat of Two-Sided Flood as Storm Bears Down

(Bloomberg) -- New Orleans is under the threat of floods from two fronts as the Mississippi River could jump to its highest point in at least 90 years.

The city is facing flood waters coming down the Mississippi from the U.S. Midwest after months of rain. Now there’s the possibility of a hurricane in the Gulf of Mexico, and the storm could push a wall of water into the coastline when it’s forecast to slam down on Saturday. The combination means the river could get within 1.3 feet (0.4 meter) of its all-time highest crest set in 1922 and will likely be higher than anything seen since 1929.

“It is something that hasn’t happened in quite a while,” said Jeff Graschel, service coordination hydrologist with the Lower Mississippi River Forecast Center in Slidell, Louisiana. “It would be the highest modern-day level.”

Following flooding in the 1920s, the Army Corps of Engineers built a series of controls that have kept the Mississippi in check in recent years. However, heavy rains across the U.S. have pushed the river into flood stage since January.

The Army Corps has twice opened the Bonnet Carre spillway about 28 miles (45 kilometers) upstream from New Orleans to control the Mississippi’s waters near the city this year.

Forecasters are watching a potential storm in the Gulf that could become Hurricane Barry in the next several days as the weather pattern heads for Louisiana. Depending on where it hits, it could send 3 to 5 feet of surge up the already bulging Mississippi, testing the city’s levees.

The last time there was the confluence of high water on the Mississippi with a tropical system was in 2009, but there was only a 2-foot rise then, Graschel said.

If the Mississippi reaches its forecast crest, it would be the sixth-highest on the river. But during previous record-setting bulges, the highest crests came during spring-time events and not because of a tropical system, Graschel said. That sudden surge of water creates more pressure on the flood controls.

“Hopefully, it will come in much lower than that,” he said, referring to the crest forecast.

To contact the reporter on this story: Brian K. Sullivan in Boston at bsullivan10@bloomberg.net

To contact the editors responsible for this story: Tina Davis at tinadavis@bloomberg.net, Millie Munshi, James Attwood

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