CHAUVIN, La. (AP) — Isaac was on the verge of ballooning into a hurricane Tuesday that could flood the coasts of four states with storm surge and heavy rains on its way to New Orleans, where residents hunkered down behind levees fortified after Katrina struck seven years ago this week.
Shelters were open for those who chose to stay or missed the chance to get away before the outer bands of the large storm blow ashore ahead of a forecast landfall in southeast Louisiana on Tuesday night or early Wednesday.
The U.S. National Hurricane Center in Miami predicted Isaac would power up to hurricane strength, which is measured by winds of 74 mph, later in the day. It could be at least a Category 1 hurricane by the time it's expected to reach the swampy coast of southeast Louisiana.
In Houma, a city southwest of New Orleans, people filled a municipal auditorium-turned-shelter. In the bayou country of Terrebonne Parish off Highway 24, storms pose a perennial dilemma for those living a hardscrabble life.
While some of the homes along Bayou Terrebonne and other nearby waterways show signs of affluence, this section of Louisiana 24 is mostly lined with trailer homes or small, often run-down houses. Staying could be dangerous, but many here who could be in harm's way have nowhere to go and little money to get there, especially given the high price of gasoline.
Monica Boudreaux lives in a trailer on low-lying land but was talking Tuesday morning with a cousin who lived closer to the bayou. They and two friends chatted as the storm approached. Boudreaux laughed when asked what she'll do if the storm hits.
"I'm surrounded by all family," she said, referring to her friends as well as her cousin. "I'll just pick up my little fat feet and run, I guess."
Forecasters warned that Isaac was a large storm whose effects could reach out 200 miles from its center. Water may be worse than wind because the storm could push walls of water while dumping rain to flood the low-lying coast in Louisiana, Mississippi, Alabama and the Florida Panhandle.
So far, the main damage in the United States was political: Republicans cut one day off their presidential nominating convention in Tampa in case the storm struck there, though in the end it bypassed the bayside city. Isaac is also testing elected officials along the Gulf from governors on down to show they're prepared for an emergency response.
Isaac's track is forecast to bring it to New Orleans seven years after Katrina hit as a much stronger storm on Aug. 29, 2005.
This time, federal officials say the updated levees around the city are equipped to handle storms stronger than Isaac. The Army Corps of Engineers was given about $14 billion to improve flood defenses, and most of the work has been completed.
New Orleans Mayor Mitch Landrieu did not activate a mandatory evacuation Monday. Instead, officials urged residents to hunker down and make do with the supplies they had.
But with landfall expected near the Katrina anniversary, anxiety was high, especially in the Lower 9th Ward, wiped out by Katrina after floodwalls burst and let the waters rush in.
"I don't really trust the levees," said Robert Washington, who planned to evacuate along with his wife and five children. "I don't want to take that chance. I saw how it looked after Katrina back here."
He leaned over the banister of his porch railing and looked out onto empty lots where houses stood before Katrina. His neighborhood, just a few blocks away from where the floodwall protecting the Lower 9th Ward broke open, remains largely empty.
Isaac had begun pelting the Alabama coast with intermittent downpours Tuesday morning — one moment it was dry, and the next brought rain blowing sideways in a strong breeze. The boardwalk at the tourist town of Gulf Shores was virtually deserted except for John McCombs, who ventured out to see waves lapping at the seawall at the public beach.
Within moments he was drenched and running for cover as a band of rain hit the wooden walkway.
"That's it. It's here," he said, scurrying back across the street.
One question haunting locals is how much oil left over from the Gulf oil spill in 2010 might wind up on the beaches because of Isaac. Experts believe large tar mats lie submerged just off the coast, but no one knows where they are or how many might be in the Gulf.
Early Tuesday, Isaac was packing top sustained winds of 70 mph. The storm system was centered about 105 miles south-southeast of the mouth of the Mississippi River just before 8 a.m. EDT and moving northwest at 7 mph, according to the National Hurricane Center in Miami.
Although Isaac's approach on the eve of the Katrina anniversary invited comparisons, the storm is nowhere near as powerful as Katrina was when it struck. Katrina at one point reached Category 5 status with winds of more than 157 mph, and made landfall as a Category 3 storm.
Still, forecasters at the National Hurricane Center warned that Isaac, especially if it strikes at high tide, could cause storm surges of up to 12 feet along the coasts of southeast Louisiana and Mississippi and up to 6 feet as far away as the Florida Panhandle.
The levees surrounding New Orleans are designed to withstand far more than that 12-foot surge, in some cases storm surge as high as 26 feet. The city's flood control system can pump out an inch of water per hour for the first hour, and a half-inch of water each hour after that.
Rain from the storm could total up to 14 inches, with some isolated areas getting as much as 20 inches, along the coast from southeast Louisiana to the extreme western end of the Florida Panhandle.
On Tuesday morning, there were few signs on the city's famed Canal Street that a tropical storm or hurricane was imminent. A group of apparently intoxicated tourists asked 30-year-old Adrian Thomas to snap their photo as he scanned the headlines of The Times-Picayune in a newspaper box.
Thomas said he was waiting for his father to wire him money so he could leave for his hometown of Greenville, Miss., which is along the Mississippi River more than 200 miles from the coast. However, he said he might not make it out in time — and he was just fine with that.
"I believe it's going to be all right," he said. "If I have to stay here and ride it out, I'll ride it out."
Burdeau reported from New Orleans. Associated Press writer Michael Kunzelman in New Orleans and Jay Reeves in Gulf Shores, Ala., contributed to this report.