NEW ORLEANS (AP) -- Isaac's whistling winds lashed this city and the storm dumped nearly a foot of rain on its desolate streets, but the system of levee pumps, walls and gates appeared to withstand one of the stiffest challenges yet. To the north and south, though, people had to be evacuated or rescued as Isaac lingered over Louisiana.
The rain fell almost constantly for more than a day, flooding neighborhoods in a rural part of the state and in neighboring Mississippi. Officials had to respond quickly because the waters were rising fast - even as Isaac meandered slowly northward Thursday on a path toward Arkansas.
President Barack Obama declared federal emergencies in Louisiana and Mississippi late Wednesday, allowing federal aid to be freed up for affected areas.
Along the shores of Lake Ponchartrain, officials sent scores of buses and dozens of high-water vehicles to help evacuate about 3,000 people as rising waters lapped against houses and left cars stranded. Floodwaters rose waist-high in some neighborhoods, and the Louisiana National Guard was working with sheriff's deputies to rescue people stranded in their homes.
A tow truck driver was killed Thursday morning when a tree fell on his truck in Picayune, Miss., just across the state line from Louisiana. Authorities said Isaac was causing heavy rain and strong winds at the time. They did not release the man's name.
Even as Isaac weakened on its slow trek inland, it continued to spin off life-threatening weather including storm surges, inland flooding from torrential rain and potential tornadoes.
Early Thursday, a Coast Guard helicopter hoisted a couple and their dogs from a home in LaPlace, near the lake, after storm surge poured into their neighborhood and local authorities called for help. The couple was taken to New Orleans and reported in good condition.
"The husband and wife and their two dogs were in an area where a lot of houses washed away," said Lt. Cmdr. Jorge Porto. "They used a flashlight inside the house as a signaling device, which made all the difference in locating them effectively."
The floodwaters "were shockingly fast-rising, from what I understand from talking to people," Lt. Gov. Jay Dardenne said. "It caught everybody by surprise."
Isaac arrived seven years after Hurricane Katrina and passed slightly to the west of New Orleans, where the city's fortified levee system easily handled the assault.
"Unfortunately, that's not been the case for low-lying areas outside the federal system, in particular lower Jefferson and Plaquemines parishes," said Louisiana Democratic U.S. Sen. Mary Landrieu. "Hurricane Isaac has reinforced for us once again just how vulnerable these critical areas are. We must re-engage the Corps of Engineers on this."
Jerry Larpenter, sheriff in nearby Terrebonne Parish, said he thinks the storm's impact took many by surprise.
"I think a lot of people were caught with their pants down," he said. "This storm was never predicted right since it entered the Gulf. It was supposed to go to Florida, Panama City, Biloxi, New Orleans. We hope it loses its punch once it comes in all the way."
New Orleans' biggest problems seemed to be downed power lines, scattered tree limbs and minor flooding. One person was reported killed, compared with 1,800 deaths from Katrina in Louisiana and Mississippi. And police reported few problems with looting. New Orleans Mayor Mitch Landrieu ordered a dusk-to-dawn curfew.
But in Plaquemines Parish, a sparsely populated area south of the city that is outside the federal levee system, dozens of people were stranded in flooded coastal areas and had to be rescued. The storm pushed water over an 18-mile levee and put so much pressure on it that authorities planned to intentionally puncture the floodwall to relieve the strain.