Since 1990 I have been leading students on an annual jazz trip to New Orleans for a three-credit American-studies course. Before the ravages of Hurricane Katrina, that was an unambiguous joy. Spending time in New Orleans takes students directly to the heartbeat of American musical culture. We journey into African-American and Latin neighborhoods typically shunned by tourists and hear jazz, blues, zydeco, Mardi Gras Indian, brass band, Tex-Mex, and other subgenres of New Orleans music, some of which have been rocking since the French encouraged slaves to practice drumming rhythms in Congo Square. This is a hands-on Emersonian project where students visit artists in their homes, attend jam sessions, sing and play on celebrated stages, and enter into the multiethnic street life of musical communities.

In pre-Katrina days, we marched in jazz funerals — for Danny Barker and the widow of Anthony (Tuba Fats) Lacen — and visited sacred shrines such as the site (now Hula Mae's Tropic Wash and Beach Cafe on Ramparts Street) where Fats Domino and Dave Bartholomew cut some of their first records; we crowded into the cramped WWOZ studio in Louis Armstrong Park, a radio station that began playing New Orleans music well before its recent surge in popularity, and that has always invited us on the air. Rather than lining up at tourist venues in the French Quarter, we went to neighborhood joints where Henry Butler, Lionel Batiste, Leroy Jones, Branford Marsalis, John Boutte, and other locals wander in from their previous gigs and jam long into the night. Here jazz is not a performance but a reflection of life on the streets, the pulse of an African-American reality that has little to do with what we hear when these players do their touring schtick at Lincoln Center or Carnegie Hall.

This trip benefits from a rich network established over the years with musicians, scholars, and club owners. Kermit Ruffins, trumpet player and founder of the Rebirth Brass Band, invites us into his home in Treme and cooks barbecue for us on his porch. Jack Belsom, the premier authority on New Orleans opera, lectures on French Quarter history and shows us the formidable opera-LP collection in his charming shotgun single on Barracks Street. In the smaller joints on Rampart Street, the neighborhood where jazz started, we are greeted the minute we walk in the door; one year when we arrived at Donna's, the owner introduced us at the bar to Mayor Ray Nagin (and where else should the mayor of New Orleans be?), who interrupted the music to make a raucous speech on our behalf.

On the trip, students in the Westminster Choir College, the music school of Rider University, are invited to sing on the stages of Le Bon Temps Roule, the Blue Nile, and other venues. I got the idea several years ago in Donna's when an unidentified woman with an astonishingly powerful voice got up and sang. When I asked her who she was, she told me she was an opera singer from London: "I've just always wanted to do this," she beamed. Band leaders now know that the Westminster students I bring in have brilliant voices that will blow the locals away every time. "Don't sing any more of those high notes, you might break our wine glasses!" shouts Bob French, leader of the Original Tuxedo Jazz Band. Westminster kids usually have a few jazz standards in their repertory, but they rarely get to improvise with a real jazz band, to experience the transcendent "self-abandon" Kurt Weill once described as unique to the idiom.

This year I approached the trip with trepidation. At first the class was scheduled, as always, for January intersession. The dean's office wanted to know: How can you take students to a place that no longer exists? The city was in ruins, and January did seem too early. Still, I couldn't bear abandoning the Big Easy; I was having apocalyptic nightmares that I knew would not end unless I went ahead with the course. So I held my breath and scheduled the trip for mid-May, right after exams.

So what's it like now? Mardi Gras and Jazz Fest are credited with bringing in a temporary infusion of business, but the critical question is how the music scene is doing during a regular downtime.

Many commentators have declared that New Orleans's unique musical heritage is either dead or irrevocably damaged. The neighborhoods from which jazz and brass bands emerged were precisely those destroyed by Katrina, the argument goes; the displacement of the people who support the music means the tradition may never be back. As Ben Sandmel, author of Zydeco! and a member of the Cajun band the Hackberry Ramblers put it, "A lot of people said New Orleans was finished, that the music was washed away by the water."

At first it appeared the doomsayers might be right. When we arrived on May 13, the airport was a ghostly shell, especially dismaying for a Saturday, and the city streets were empty; even the French Quarter had an eerie serenity. But the minute we got into the clubs, everything burst into life.

Bulletin: Music in New Orleans is not over. The best of the splendid little dives — Vaughan's, Donna's, the Maple Leaf, Rock 'n' Bowl, Snug Harbor, the Spotted Cat, d.b.a. — are all up and running and packed with exultant, grateful locals. The critics who say jazz is lost in New Orleans are the same ones who were saying it before the hurricane; indeed, the self-appointed arbiters of the True Jazz have been decrying its demise or degradation for 75 years, since the founding of the Hot Clubs and the birth of bebop. "The jazz is dead" lament is an institution, an indelible part of jazz culture.

Meantime, New Orleans rocks on. Yes, some 300,000 people are apparently not coming back, an unimaginable tragedy. But many fanatical followers of New Orleans jazz, blues, funk, Cajun, klezmer, and other genres continue to stream into the clubs. If there are fewer drunks from Ohio and Texas lurching about in the Quarter, that is just as well. "Those aren't the people who support music," says the bass player Peter Harris, of the New Orleans Hot Club. "Those are the people who support Bourbon Street."

The contrast between the emptiness in the streets and the ecstasy in the music bars is the bittersweet signature of the new New Orleans. "We're durable," says Charlie Sims, the 71-year-old owner of Donna's, which reopened October 15 to celebrate its 10th anniversary and still holds glorious improv nights on Sunday and Monday evenings. Sims, a former chef on the Southern Crescent railroad (he serves the best barbecue chicken in town free on Monday nights), points out that the sports bar around the corner remained open throughout the hurricane's aftermath. The bartender at the Maple Leaf proudly states that George Porter Jr. and Walter (Wolfman) Washington played gigs there before and after the devastation, using electric generators when everything went dark, as club owner Hank Staples guarded the door (and the door of the fabulous Jacques-Imo's restaurant next door) with a shotgun. John Blanchard's Rock 'n' Bowl (yes, they do both there) remained the only business open in the huge, devastated Tulane-Carrollton area; Blanchard was on the verge of shutting down in the fall but stuck it out when electricity was restored in October.

The scene is certainly different now: more intimate, more focused, and with unpredictable configurations. You never know who you are going to hear, which makes club hopping more of a New Orleans experience than ever. At Preservation Hall, which for 45 years played only Dixieland, we heard gospel — Davell Crawford leading a group of local shouters and tambourine rattlers.

At the Maple Leaf Bar, the Rebirth Brass Band, which plays regularly on Tuesday night, was joined by younger colleagues, the New Birth Brass Band, for a spectacular jam session. The Rebirth — all nine of whom lost their homes — had four of its members in New York for a gig, a typical situation for these musicians in exile, so fans got to hear different generations blasting together through the club's narrow, New Orleans-red hallway. The crowd, the biggest I've ever seen at this tough neighborhood bar, consisted of young, nontourist locals. At Vaughan's Thursday-night show, Kermit Ruffins was supposed to play, but Troy Andrews, better known as Trombone Shorty, showed up instead, apologizing that half his band was still in Nashville. No problem: Half of this charismatic young group playing in a rocking place like Vaughan's has 20 times the brilliance of anything we are likely to hear in the Northeast.

Do not believe the claim made by many critics that New Orleans music now has an "angry edge." That is the angry edge of projection, coming from burned-out music critics. Certainly New Orleans residents are stunned by the magnitude of governmental incompetence; funk and hip-hop lyrics savagely satirize the villainy of Republicans and other scoundrels, as they always have. Local after local reminded me that this city has survived not only corrupt politicians, but yellow fever, bubonic plague, two all-consuming fires, and numerous floods.

Nonetheless, the life-affirming spirit of the music — the jazz-funeral tradition of looking death in the eye and then partying anyway — is intact, with the tragic backdrop of the hurricane adding a subtle poignancy. Davell Crawford's signature version of "Amazing Grace," caressed by his silken piano glissandos, took on a new sweetness, especially at "I once was lost, but now I'm found." "We're in exile," he said of his band, several of whom commuted from Houston for a gig that brought in $8 a person at the door, "but we're here." Leon Brown, trumpet player and another lost artist, was exiled in Atlanta for months, but moved back to the Big Easy to live in a trailer because he couldn't bear being away from the music. His rendition of "Do You Know What It Means to Miss New Orleans" was heart-rending.

Two weeks after Katrina, during a news conference, Mayor Nagin looked up wistfully from a ruined landscape at a clattering helicopter. He was tired of all the noise, he told a reporter; he just wanted to hear the music again.

Now it's back. As Todd Duke, a guitarist, told me, "It's important for people on the outside to realize that there is still a lot happening musically and culturally; a lot of musicians are here, and a lot of cats that aren't here are still coming into town and playing gigs and are on their way back."

Bob French adds a New Orleans flourish: "We'll be here, drunk or sober."