NEW ORLEANS - The people of New Orleans tried all weekend to pray, curse and drink Hurricane Katrina away from the Big Easy."They've been singing this song for 30-some years, and what? Nothing," said Bertrand Coleman, who's driven mule-drawn carriages through the French Quarter for just as long. "We may pray this one away too."But by Sunday afternoon, the people from the self-proclaimed City that Care Forgot finally turned deadly serious."This is the big one," said Harry Hornet as he prepared his house in the shadow of the levees that will determine New Orleans' fate.From the banks of Lake Pontchartrain - which experts expect will gush into New Orleans - to the barren streets of the French Quarter - which is expected to flood with up to 28 feet of water - New Orleans was a city bracing for catastrophe."We've never seen a Category 5 this large before," said Max Mayfield, director of the National Hurricane Center.After hearing that kind of talk, tens of thousands continued fleeing west, north and east under an unprecedented mandatory evacuation order given by Mayor Ray Nagin shortly after 9 a.m. Sunday.President Bush urged the order when he spoke to Louisiana Gov. Kathleen Blanco earlier in the day, and New Orleans officials accepted that it was time."This is a threat that we've never faced before," Nagin said."There's seems to be no relief in sight," followed Blanco.Or, as Mike Moscona of the East Jefferson Levee District put it: "Find a place to hide."Despite the oncoming behemoth, New Orleans acted much as it always does for most of the weekend.On Saturday night, tourists and locals danced through Bourbon Street and laughed off the oncoming storm.Corey Mathias, a former New Orleans man who was visiting his old town, explained his unique way of preparing for the storm."My room is open to any damsel in distress," he hollered, a hurricane drink in his hand and a flourish in his delivery. "Just put a Red Cross outside my door and wave them in. I'm about humanity, you see."Kelley Hetterick, a bartender at a local bar, said she understood the danger, but explained her reasons for staying behind."There's a Saints game next week. Then it's Labor Day, and that's Southern Decadence weekend," Hetterick said, referring to the weekend-long festival for gays and lesbians. "These weeks are my money-makers, baby."That's just how New Orleans rolls, many explained. Life goes at a different, if odd, pace.Teresa Kinney grew up in New Jersey and never felt quite right there. She couldn't take the speed, the tension, the hectic pace of the Northeast."Now, I'll call people up there and they tell me, 'You speak so slowly,'" she said.Kinney has been "schlepping around" the French Quarter for years now, where she continues running her courier service back in Jersey, but at her own pace."I was tired of the running around, the screaming, the yelling," she said. "So when I got here, it was like a different world. I can still walk around the corner and see some new thing or meet some amazing person."You've just got to feel it."But that feeling took a major shift toward overwhelming tension starting early Sunday morning.Many remember Hurricane Camille in 1969, which battered the area and killed 256 in Louisiana and Mississippi. They remember Betsy in 1965, which made landfall in New Orleans with 115 mph winds.So when they hear reports of the 190 mph wind gusts that Katrina was lashing out by Sunday afternoon, few are ashamed to admit that they're running."I knew it was going to hit one day. But I was just hoping I'd be gone by then," said Hornet, a 65-year-old retired physician who continued glancing at the levee that separates his house from Lake Pontchartrain.The levees along the lake and the others that surround New Orleans are the keys to determining whether the city floods or not.With Lake Pontchartrain to the north, the Mississippi River to the south and swamp land all around, New Orleans actually rests below sea level. So the city depends on those levees and the extensive pump system that cranks water out of the city to keep New Orleans dry.But scientists at Louisiana State University have told city officials that their system is no match for a Category 4 or 5.The worst case: The oncoming storm with winds out of the southeast forces water in Lake Ponchartrain to swell and rise as the areas east of New Orleans begin to flood. As the storm moves north, the wind would turn and start battering the city from the northeast, pushing that water over the levees and sending billions of gallons of water into New Orleans.At that point, water in the bowl-shaped city would rise and surpass the water level around it, leaving the pumps and levees useless. Add gators, snakes, nutria, rats, mosquitos, red ants, throw in the sewage that will fill the water and the polluted waters of the Mississippi, and the potential for disease is almost as frightening as the winds of Katrina."That's where you'd expect the most casualties from a storm," said LSU biology professor Neil Simonsen.That realization has set in to the locals."The storm surge most likely will topple our levee system," said Mayor Nagin.The city is preparing 30 boats to get rescue, law enforcement and city officials around town. Nagin issued an order Sunday morning saying city officials could confiscate vehicles and boats during the hurricane, a "last resort" Nagin said could be used if more boats are needed.Is there any other plan B?"The president, I'm sure, is going to send us what we need," he said.But still, some stay, even though it's hard for them to explain why.Hamp Lyness, who lives in the shadow of the levees along Lake Ponchartrain, explains his decision to stay like this."That's the lake. So I'm not going to get a tidal wave here, right?" said Lyness, an articulate stockbroker who was cutting down a crepe myrtle in his front yard so it wouldn't topple his power lines.Some just had nowhere to go.Across the Mississippi River in the ramshackle area of Algiers Point, Lynnette Klees explains that she can't afford a drive up north and a potentially lengthy hotel stay. She'll stay in her 100-year-old, wooden shack with her eight cats and hope that the levee - just a few blocks away - stands up to Katrina."If the water comes up, I'll get in my attic," she said. "If it keeps rising, I could always blow out the back window and get on the roof."She pauses."Oh wait. I guess the wind would get me there, huh? OK, how about this? If the levee floods, everybody's going under."Across the river in the French Quarter, a fire crew roamed up and down the streets, someone blaring into the loud speaker to leave the city."Mandatory evacuation. Run for your lives."Richard Wharton heard the calls but refused to leave his Bourbon Street bar.The Tricou House is owned by a friend and Wharton is now running it. He said he will ride out Katrina: "They're saying the floods are 18 feet? That balcony is exactly 18 feet, so I'll be fine."Wharton joked and brushed aside questions of fear and second-guessing his decision.But he trots outside his bar for a moment when asked what could happen to the French Quarter if those flood and wind reports actually ring true.Wharton, a square-jawed and barrel-chested man who had spoken in a matter-of-fact tone until that question, took a slow, deep sigh."Trying to predict that is like looking at the sky and wondering how many stars there are," he said, a drunk friend behind him vigorously nodding his head. "That's a lot of water, man."Eric Bartley was planning on riding out the storm with two deep-sea fishing rods, eight two-liter bottles of Coca Cola, a fresh pot roast and some already-cooked macaroni. While talking to an old friend beside the Lake Lawn Metairie Cemetery - one of the many New Orleans cemeteries filled with majestic, Gothic tombs standing above ground because the area is below sea level - he looked back at the untouched cemetery and sighed."Even the dead are going to have to take care of themselves on this one," he said.His friend, Lamont Williams, laughed for a moment before turning serious."This town is not ready for this," said Williams, a bus driver who will be on call throughout the storm. "We've never had whole subdivisions blow away. We've never had a house lifted up and moved down the street. How do you pick up the pieces from something like that?"In typical New Orleans fashion, someone had an answer for Williams. It was Mathias, the slightly inebriated fellow who had offered his room to the distressed women of New Orleans.In a clear moment, Mathias put his arm around a friend and explained what would happen if Katrina, true to her hype, came in and washed the Big Easy clean."The thing you have to remember is that it's not these buildings that makes New Orleans, it's the people," he said. "New Orleans, man, will always live on, regardless of what happens."Or, as stranded tourist Rob Longo put it: "Somehow, the party will go on."