Imagine a wave so big it darkens the horizon as it rolls in.

Just south of San Francisco, this surf spot is called Mavericks.

Sarah Gerhardt is the first women to surf this famously dangerous big-wave spot. She did that in 1999 when she was 24. Now, at 42, she's one of six women comprising the first women's heat in a surfing contest there.

The women will compete for $30,000 in the Titans of Mavericks, surfing waves that swell well beyond 30 feet.

"Mavericks is the best big wave spot in California, regularly 40 to 50 and sometimes 60 to 100 feet tall with huge rocks, and there's a shark attack out there every year," Gerhardt tells NPR. "People's leashes have been caught in the mouths of sharks, and it is very cold. That water temperature gets down to 48 or 49 and then of course the air temperature in the winter can get be in the 30s or 40s. It's terrifying — but I wanted to surf it anyway."

Gerhardt started surfing as a teenager, and eventually was lured by big waves — even though, she says, they left her "trashed." "I loved it, and I never looked back," she says. "I always wanted to be out in bigger surf."

Paddling up to the top of that first Mavericks wave, she says, her brain told her "Don't go!"

"And then ... all of a sudden you're going 30 miles an hour heading into oblivion," she says. "And when I kicked out I was like, 'Wow, I can't believe that was so amazing. I want to do that again.' "

As part of the first women's heat in the Titans of Mavericks event, she hopes to inspire younger surfers. "Women surfing big waves has not peaked yet, and it's just going to get better and better and better," she says. "And it kind of feels almost like closure, and that I can pass the torch on to that next generation who's coming after me."

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