Ever since fate brought me to live in New Orleans, I have been full of complaints. First of all, like most life-long New Yorkers, I couldn’t imagine living anywhere else but New York City. Plus I never could get interested in the commercialized decadence of Bourbon Street; the flowery cliches of haunted mansions, and jazzy joie de vivre rubbed me the wrong way. All that romantic nonsense seemed to me like a bad perfume, covering up the real stink of a troubled city.

We moved to New Orleans because my partner got a good job at a university there. Despite some reluctance, I tried to participate in the place I had landed. I danced late at night on sticky floors to the melancholic strains of Cajun zydeco music. I read George Washington Cable’s stories of old Creole life. I walked my dog in the mud of the Mississippi River levee as the lightning crackled before a storm. I ate every variety of deep-fried marine life possible until I could barely waddle away from the dinner table.

We had arrived in mid-August. August is not a good time to come to New Orleans. New York has its own humid days, but nothing compares to the swampy conditions of New Orleans. Air-conditioning is a futile defense. Nature, in general, seemed grotesque: the tough cockroaches of Manhattan would turn and run if they saw the bizarre insects of the Big Easy. And while New Yorkers are used to potholes, the streets of New Orleans resemble a minefield. Even the sidewalks have broken down in many places. No municipal force of sanitation ever seemed to penetrate the torpid air of those smelly summer days.

And then, a month after we arrived, it was September 11. I already was missing New York and its familiar comforts, but now I really learned what it meant to miss home. I remember that day, racing back to our apartment in Uptown New Orleans, looking with blinking disbelief as I drove past the slow-moving streetcar and the genteel mansions of St. Charles Avenue. It seemed impossible that there could be such catastrophe one place and such calm elsewhere. If there were more attacks to come – and in the weeks after September 11 many expected them – didn’t I want to be with my friends and family? Being away from home is one thing, but what if home should vanish entirely while you’re not there?

I yearned for the familiar; New Orleans seemed unreal. Some people put American flags in the window, but otherwise life went on much as before. My friends in New York sounded full of urgency, they spoke of neighbors coming together, strangers embracing: History was upon them in the most dramatic and terrible way, and I felt more alone than ever in this irrelevant place, this jasmine-scented Brigadoon, a decrepit city, fallen out of time.

Now it is another September, four years later, and I am once again watching another disaster from far away, since we happened to be back in New York when Hurricane Katrina hit. As the first footage of the flooded city appear, we see familiar sights, bloated and distorted by water. There is the suburban movie theater with cars bobbing in its parking lot like boats in a marina; there is the little Vietnamese restaurant we love with water over its doors; that boat is speeding past our post office, now eerily submerged.

Our friends are all displaced people now, depending on the kindness of Baton Rouge and Houston, more functional, if less interesting, cities. As terrible as September 11 was, at least most New Yorkers were able to stay in their homes and assist one another. Perhaps one of the worst aspects of Katrina is that the refugees of New Orleans have been scattered in a thousand directions. New Orleans is a culture of the group, of parades and clubs and neighborhoods whose identity hasn’t changed in decades; now its inhabitants have been sent into a peculiarly lonely exile.

It is a truism in New Orleans that its residents don’t like to leave the city ever, even for a vacation, even just to go to Baton Rouge. There is an attachment to the city and its traditions so fierce it can seem claustrophobic. The people of New Orleans are extremely hospitable to strangers, but they are also deeply insular, bound up in their traditions and families. This is why so many will try to return, despite the social failures of the city, despite the current devastation, despite the possibility of another hurricane.

Everywhere around us, regional differences seem to be slipping away. However, New Orleans defies that trend. It continues to be a little world all its own. It has its own cuisine, its own slang, its own rules and its own calendar, full of idiosyncratic holidays and festivals.

Friends in New York assume, for example, that Mardi Gras is a spectacle for tourists and drunken college students. Nothing could be further from the truth. Rich and poor, white and black, young and old, practically everyone ends up sewing costumes and organizing floats for the three-week long celebration. Every year, local public television carries full coverage of the different balls and their elaborate ceremonies. What will happen now to these traditions and the people who are nourished by them?

New Yorkers can be parochial, but New Orleanians have them beat. In New York, neighborhoods change their identity from one generation to the next, giving way to the next wave of immigrants or artists. New Orleans, lacking the economic wherewithal to attract ambitious newcomers, clings proudly to the past. It has made a culture and an industry out of its own self-fascination. Generational stasis is a matter of civic pride. Little old ladies go to the same neighborhood restaurants where their parents went. The famous above-ground mausoleums are better kept than some of the public housing. For all its flaws, New Orleans has kept faith with its ghosts, and in our age of relentless forgetting, that gives the city a weird but admirable integrity.

Doom has been hanging over New Orleans since its origins. It has survived hurricane, war, fire, plagues, and floods, and a long slow diminishment in wealth and importance. For over a century before Katrina, it has been a city looking back on its lost glory, a culture of nostalgia. Now there is a massive diaspora, possibly a permanent one. The people of that city are not only mourning their human and material losses, as tragic as they are, but something intangible: a culture that sustained them. If New Orleans never recovers, a million people will look back at this drowned city as their lost Jerusalem.

Mr. Ravitch is a writer based in New York and New Orleans.