Floodwater from Hurricane Isaac jumped a levee on the outskirts of New Orleans on Wednesday, but the multibillion-dollar barriers built to protect the city itself after the 2005 Katrina disaster held firm, officials said.
The lumbering hurricane, which weakened to a tropical storm Wednesday afternoon, threatened to flood towns in Louisiana and neighboring Mississippi with a deluge of rain, storm surges up to 12 feet and top sustained winds up to 70 mph.
U.S. Highway 90, a key interstate roadway on Mississippi’s Gulf Coast, was washed out by the storm, which triggered widespread power outages and was expected to bring rainfall accumulations totaling as much as 20 inches to some areas.
“The federal levee system ... is fine,” New Orleans Mayor Mitchell Landrieu told local radio. “There are no risks. It is holding exactly as we expected it to and is performing exactly as it should.”
As torrential rains fell on the city, Landrieu later cautioned that it was too soon to declare victory.
“We are very much in this fight of Hurricane Isaac,” he said. “Unfortunately this storm just won’t seem to leave us.”
Tree limbs and street signs littered the streets, and power was out in much of the city, which was devastated by Hurricane Katrina exactly seven years ago.
Authorities reported no security problems, other than four arrests for looting, but Landrieu said he was clamping a dusk-to-dawn curfew on New Orleans nonetheless.
“We’re going to have a zero tolerance for lawlessness during this emergency,” he said.
In low-lying Plaquemines Parish, which stretches southeast from New Orleans, emergency officials reported the overtopping of an 8-foot-high levee between the Braithwaite and White Ditch districts.
Isaac was wobbling northwestward near 6 mph, a slow pace that increases the threat of rain-induced flooding.
More than 730,000 homes and businesses along the coast of Louisiana and Mississippi remained without electricity Wednesday evening.
*Includes Entergy New Orleans, Entergy Louisiana and Entergy Gulf States units.