It was hard to predict which would begin first — the Santa Fe Symphony concert at Fort Marcy Park or the thunderstorm bearing down on the hundreds who had gathered for the 400th anniversary celebration's "Under the Stars" concert and picnic on the ball park.

As it turned out, it was a tie. As the 74 members of the symphony opened the event with Verdi's "Triumphal March" from Aida, the skies opened up and concertgoers — such as Warren and Barbara Wheaton and company — turned canvas picnic ground covers into makeshift storm shelters.

"It could be a Woodstock kind of thing with a bunch of people in the mud," said concertmaster David Felberg as dark clouds, streaked with occasional lightning, thundered toward the park earlier.

The symphony's musical director and conductor, Steven Smith, said the concert would go on rain or not, with the symphony performing a vibrant selection of music chosen especially for the Viva Santa Fe celebration. Besides the Verdi piece, the concert included the Carmen Suite by Bizet, Leonard Bernstein's West Side Story, Gershwin's "Cuban Overture" and John Williams' "Cowboys Overture" and other selections.

Penelope Penland, the symphony's chief fundraiser, said the musicians, performing under a stage cover, would press on unless and until the weather conditions posed a threat to their instruments.

As it turned out, the concert was interrupted several times for the musicians to protect their instruments, and the performance was cut short by about 45 minutes. The show's fireworks, however, went off as planned for those who endured the rain.

The concert marked the closing of Santa Fe's opening event celebrating the founding of the city.

Picnickers included the hundreds who parked themselves in the outfield grass for $12 apiece. They were separated by the infield dirt from those who paid $30 for a chair on the infield grass.

Gerry and Patty Hotchkiss of Santa Fe sat on chairs, umbrellas at their side, minutes before the performance began. Gerry Hotchkiss, who at one time was a vocalist for the symphony, marveled at the festive flavor of the selections.