Plowing in as a Category 2 storm from the Gulf of Mexico, Gustav packed 110-mph winds but quickly dropped to Category 1. It crossed coastal lowlands dominated by oil pipelines and fishing wharves and headed toward east Texas. By late Monday, it was downgraded to a tropical storm, with sustained winds of 60 mph.
Even as Gustav moved into Louisiana's interior, Hurricane Hanna was forming over the Bahamas. National Hurricane Center forecasters predicted the new storm, which had winds of 80 mph Monday night, could reach the southeastern U.S. by midweek.
By day's end, New Orleans had escaped a catastrophic replay of the destruction left by Hurricane Katrina three years ago. The unprecedented mass evacuation of 1.9 million people emptied the hurricane zone and appeared to have spared the region from heavy casualties.
Authorities reported eight storm-related deaths, all but one from traffic accidents -- including four in Georgia. An additional three fatalities were reported during the evacuation of New Orleans. Gustav was blamed for at least 94 deaths in the Caribbean.
Public officials remained guarded in their assessments but grew increasingly optimistic that the city had missed the brunt of the storm. A relaxed New Orleans Mayor C. Ray Nagin said Monday night that he felt "really good" about the city's status.
"The city of New Orleans is not totally out of the woods, but we're getting close," he said, adding that today would be "a day of repair and assessment."
"I would not do a thing differently," he said. "I'd probably call Gustav, instead of the mother of all storms, maybe the mother-in-law or the ugly sister of all storms."
Companies would probably be allowed to return Wednesday to prepare for a repatriation of the city's population. "Re-entry is only days away, not weeks away," Nagin said.
The city's most anxious moments came as floodwaters streamed over levee walls along the Industrial Canal, the artery that connects the Mississippi River with Lake Pontchartrain.
The canal's levee walls overflowed in two spots and floodwaters seeped into the low-lying streets of New Orleans' Upper 9th Ward -- the scene of major flooding during Katrina.
But by midafternoon, a National Guard team making checks on the canal reported that water levels had dropped nearly two feet, a welcome hint that the worst of Gustav's storm surge had passed.
"It's dropped at least 18 inches, if not two feet," said Louisiana National Guard Lt. Col. Freddy Morris, commander of the 256th Special Troop Battalion, who led a team that inspected levees. "I'm feeling a little better."
After monitoring southern Louisiana levees for much of the day, officials with the U.S. Army Corps of Engineers expressed optimism that the major repairs they had begun after Katrina had held. More than 350 miles of federal levees protecting the city were spared the devastating failures of 2005.
"The system proved resilient," said Maj. Elizabeth Robbins, a Corps spokeswoman.
Other Corps officials were guarded in their comments.
"It's much too early to say they've been a success because the winds are still moving very strong," Maj. Gen. Don T. Riley said at a news briefing in Washington. He added: "We would not be pounding our chest at this point."
South of New Orleans, a sodden levee along a bend in the Mississippi River near the town of Braithwaite breached just before dusk, threatening several dozen houses. The floodwall, in Plaquemines Parish, is not part of the federal levee system.
Dan Ragas, a parish equipment operator, said they would firm up the floodwalls if it took all night. "Look around," he said, gesturing to the small army of men in mud-spattered boots. "These people are out there making it happen."