More than 1,000 fans are expected at this year's Thrasho de Mayo festival, drawn by rising upstart local metal acts and some of the genre's heaviest hitters.

But no one expected it to get so big. Particularly not Esther Gutierrez, a housewife who put the first one together at the Whisky A Go Go in 2006. At the time, she had no idea she was helping to birth a resurgence in Los Angeles thrash metal.

“I was just a mom helping her son's band,” Gutierrez explains, adding that back then she knew next to nothing about the genre. Her son, Carlos, had just turned 18 and was drumming in Fueled by Fire, a local metal group primarily playing backyard shows. “Initially, they were having trouble booking club shows because they were all teenagers,” she says. “I felt for the kids and wanted to help them out.”

Thrasho De Mayo's first lineup featured unsigned local groups full of teenagers. But their collective buzz — mainly from the backyard scene — nonetheless drew an overflow crowd to the Whisky. In fact, it's fair to say its success kick-started label and promoter interest in the L.A. thrash scene.

“It was such a major turning point for thrash in L.A.,” says Warbringer guitarist John Laux, who also played on the bill that day. The group has since recorded three albums for Century Media and performed hundreds of shows worldwide with well-known acts like Napalm Death and Soilwork. “There were always backyard shows, but it was cool that local bands were packing the Whisky. That show belonged to us. It's hard to ignore something like that.”

The players had an important ally on their side. Katon W. De Pena, vocalist of '80s L.A. thrashers Hirax, had seen a couple of the bands at smaller shows and offered to emcee the event. After all, acts such as Hirax, Agent Steel and Dark Angel had led L.A.'s thrash scene in the mid-'80s, and his endorsement of this new wave of Los Angeles thrash metal meant a lot.

Three of the five bands who performed that day — Fueled by Fire, Merciless Death and Warbringer — were signed within a year, by Metal Blade, Heavy Artillery and Century Media, respectively. Soon they found themselves spreading the gospel of new L.A. thrash and touring worldwide with name acts like Exodus and Overkill, some of whom had been slogging it out since before these kids were born.

Thrasho de Mayo itself would continue to grow as well, adding notable out-of-town headliners (like San Francisco's Heathen in 2008 and German thrashers Exumer in 2009) who hadn't played Los Angeles in years, to go along with the rising locals. In subsequent years the festival sold out both rooms of the Knitting Factory, before going on hiatus after the 2010 festival.

Perhaps not coincidentally, the local thrash scene started to slow around that time, too. Merciless Death broke up, and Fueled by Fire got dropped by Metal Blade.

But we're now seeing yet another resurgence, with an even newer wave of metal bands inspired by the ones that sold out the Whisky in 2006. Insentient are up-and-comers, while Warbringer and Fueled by Fire both have new albums and are touring later this year.

“The community had gotten lost for a while due to competition between bands and promoters, but it's starting to come back together again,” Esther Gutierrez says. “Now there's a new wave of bands and everyone is united again around that.”

Headliners for this sixth installment include '80s hardcore moshers M.O.D., Bay Area gore-metallers Ghoul and — playing on the West Coast for the first time ever — reunited '90s Wisconsin thrashers Morbid Saint. Rising SoCal bands include O.C. death-thrashers Madrost and L.A. thrash-punkers Xpulsion.

As for Gutierrez, she's now a bit hipper to thrash music. “I thought it was a little weird at first,” she admits. “But I realized that they are expressing their opinions about the world and getting engaged in critical thinking. You should appreciate that your kids have talent and are expressing themselves.”

Thrasho de Mayo VI takes place Saturday, May 11, at the Vex/Arts L.A. More information here.

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