TROPICAL storm Lee is lurching toward the US Gulf Coast, dumping heavy rain on Louisiana and threatening extensive flooding that will put the New Orleans levee system to the test.
Oil companies evacuated workers from offshore rigs ahead of the arrival of Lee, a disorganised but major rainmaker, while Louisiana Governor Bobby Jindal declared a state of emergency.
“Flooding is our primary concern,” Mr Jindal said, urging residents to “prepare for the worst and hope for the best.”
Officials warned the slow-moving storm could bring the same kind of flooding that residents in the northeast are still grappling with after Hurricane Irene hit a week ago, leaving nearly 50 people dead and millions without power.
With experts forecasting that Lee will turn to the northeast and push inland, one of the biggest dangers from the storm could be in the Appalachians.
“If we get the five to 10 inches (12.5-25 centimetres) that come out into a tropical storm in that kind of terrain, the flash flooding is fast and it’s violent,” Bill Read, director of the National Hurricane Centre in Miami, told reporters.
Overnight, Lee was stalled off the coast, just 75 kilometres southwest of Morgan City, Louisiana, packing sustained winds of 97km/h, the NHC said.
“Lee has been stationary the past few hours. A slow and possibly erratic motion toward the north or northwest is expected during the next 24 hours… followed by a gradual turn toward the northeast,” the center warned.
With some areas forecast to receive up to 50cm of rain over the Labor Day holiday weekend, residents of coastal states as well as landlocked Kentucky and Tennessee should prepare themselves for extensive flooding, Mr Read warned.
The head of a parish in the New Orleans suburbs, Billy Nungesser, told Fox News meanwhile his biggest concern were whether the levees would hold up.
“Twenty inches of rain, which is expected – we’re hoping that’s spread out over three days, as nowhere (here) can take that heavy rain in a concentrated timeframe,” Mr Nungesser said.
The New Orleans Times-Picayune reported several Louisiana parishes were distributing sandbags and issuing evacuation orders for the lowest-lying areas.
Lee was battering the Gulf Coast six years after the region was devastated by Hurricane Katrina.
The levee system around New Orleans failed after Katrina, putting much of the city underwater. More than 1,500 people died.
On Monday, Katrina’s sixth anniversary, the Times-Picayune reported that an upcoming Army Corps of Engineers report gives the levee system a “near-failing grade,” despite a $10 billion post-Katrina rebuilding job.
The intense rain that Lee is already dumping on the city is expected to provide the most severe test of the levee and canal systems at Lake Pontchartrain and elsewhere since Hurricane Gustav came close to overwhelming the levees three years ago.
Earlier this week New Orleans Mayor Mitch Landrieu said the water pumps that are key to the city’s flood mitigation are “100 per cent operational.”
Mississippi Governor Haley Barbour has declared a state of emergency in several counties, urging residents to prepare well in advance.
“Do not underestimate the impact of this system of tropical weather,” he said.
US forecasters are also monitoring Hurricane Katia in the Atlantic Ocean.
Forecast models vary, and Katia is still well out to sea, but some tracks show the hurricane nearing and perhaps clipping the US eastern seaboard sometime next week.