Alumni and other fans will miss out on the flames at Old Main this year.

Dean Knuth / Arizona Daily Star 2010

A huge bonfire that marks the start of homecoming weekend at the University of Arizona is going dark for the first time in UA history.

The near-century-old tradition is on hiatus because its normal venue is fenced off while Old Main, the school’s beloved first building, undergoes a $13.5 million renovation, officials said.

The Friday night bonfire on Old Main’s front lawn has been a fixture of homecoming festivities for decades. The event’s precise history is unclear, but it likely began in the 1920s, or possibly earlier, according to a UA website.

“This is the first time it’s ever been on hiatus,” said Jill Hall, a vice president with the school’s Alumni Association.

“The decision was not made lightly,” she added.

Hall said officials considered moving the event to another site, but decided against it because heavy traffic is expected across campus for the season opener of Wildcats basketball, which also is tonight.

“We’re all sad about it,” Melinda Burke, the Alumni Association’s president, said of the bonfire’s absence this year. “But our first priority is keeping everyone safe.”

The bonfire will be back next fall for the 100th anniversary of UA homecoming, Hall said. Work on Old Main is expected to wrap up by next summer.

More than 50,000 people are expected to take part in homecoming festivities this weekend.

Scheduled events include a pep rally tonight, a tailgate party and a parade, which begins at 4 p.m. Saturday on the UA Mall, led by former U.S. Rep. Gabrielle Giffords and her husband, Mark Kelly. The two will be grand marshals.

At 8 p.m. Saturday, the Wildcats host UCLA at Arizona Stadium.