This was the scene in Saratoga Springs, N.Y., last Tuesday, as Lollapalooza–a carnival of post-punk musicians and sideshow entertainments-crossed paths with a local tornado. The drenching was fast and thorough, as the power went out and upwards of 20,000 fans scurried for what little shelter was available. But when it was over, it was over. Power came back, the sun came out. The soaked women fans were glad that punk sartorial codes mandated black underwear. And for the men, there was mud wrestling. Lollapalooza, an experiment in controlled anarchy, inched just a notch closer to the real thing.

In a mixed concert season, the 30-city tour has been a startling success. Conceived by Perry Farrell, the singer in the late psychedelic band Jane’s Addiction, to unite the microcults that make up the alternative-music audience, the show features no superstar headline acts. Instead, it packs seven acts recently up from the underground: the Red Hot Chili Peppers, who mix rowdy funk and punk; scruffy rockers Pearl Jam and Soundgarden; profane gangster rapper Ice Cube; Ministry, a Chicago group that sets images of paranoia and vice to stiff, crushing rhythms, and the introverted British bands Lush and The Jesus and Mary Chain. Lesser-known musicians share the second stage with the freaks. While Bruce Springsteen, U2, Paula Abdul and Hammer are having trouble selling tickets in some cities, most Lollapalooza dates have sold out immediately. Of, course, Bruce doesn’t have Mr. Lifto.

The nine-hour concert is only partially successful musically. Most of the acts aren’t used to playing to such large audiences, and lose the immediacy they have in clubs. But as an event, Lollapalooza is eye opening. A mixture of fantasy and pragmatism, arch irony and new sincerity, it documents the arrival of the generation born after Woodstock. The concert reflects, as colorfully as Woodstock, the demands of a new generation of young Americans: what they want in sex, music, drugs, food, recreation, rhetoric and politics.

But where Woodstock celebrated personal liberation as a tonic against the anxieties of a generation being sent to Vietnam, Lollapalooza charts the caution and abstinence of a generation that has been chronically disengaged. The Woodstock generation wanted out; this generation, after years of being out, wants in. The pamphlets urge people to register to vote, not drop out. The drugs are legal “smart drugs,” the official sex safe. And the preferred kinkiness, tapped by the sideshow, is mostly voyeuristic, fitting for the age of AIDS and the reascendant go-go bar.

The alternative-music audience has long cherished its small numbers. It affects a benign elitism-the more obscure or farther from the mainstream, the better. Lollapalooza turns that around, celebrating newfound mass appeal. Surrounded by Mr. Lifto and the rest, a generation is letting its freak flag down and declaring itself the new mainstream. There’s power in these numbers. For the children of the baby bust, this marks an unqualified victory.