In Nashville, hundreds of songs are written every day by aspiring artists, but the majority will never be heard by an audience. In an industry where there’s often no rhyme or reason as to what works and what doesn’t, it’s always a triumph when a song not only breaks through, but launches an entire career.

Take “Hurricane,” the debut single from Nashville newcomer Luke Combs, whose first album (“This One’s for You”) drops on Friday. The midtempo heartbreak song is officially a smash — it has sold approximately 434,000 copies so far and recently spent two weeks at No. 1 on the Billboard country radio chart.

So why, out of all of the songs 27-year-old Combs has co-written, did that one connect so deeply with listeners? Sure, “Hurricane” has an irresistible hook, and a universal theme about a guy who runs into his ex-girlfriend just as he’s starting to move on. But mostly, it’s the perfect example of a song that inexplicably touches a nerve and changes an artist’s entire life. Even the singer himself has no idea how it happened.

“I think, obviously, it’s hard to put a finger on why people like one song versus another one. It just fits, you know?” Combs said recently in a phone interview. “It just sounds like something you would hear on the radio, and it’s taken on a life of its own.”

It’s hard to explain the “magic” of a song like that, Combs added; he certainly didn’t expect it. He wrote “Hurricane” in November 2014, shortly after moving to Nashville, where he barely knew anyone. Combs arrived in town from Boone, N.C., where he had gained a loyal following playing shows as a student at Appalachian State University and already recorded two EPs on his own.

When he arrived for a co-writing session with Thomas Archer and Taylor Phillips, Combs had an idea in his phone for a song title called “Hurricane.” After brainstorming, they decided to tell the story of one of their friends, who had recently broken up with someone. The tune opens as the narrator starts to relax at a bar, when all of a sudden, his ex walks in — and the jolt of seeing her again hits him like a hurricane. (“Then you rolled in with your hair in the wind, baby without warning/I was doing alright but just your sight had my heart storming.”)

“It wasn’t anything outstandingly memorable,” Combs recalls of the day spent writing. The trio got the first draft done and polished the lyrics a few weeks later. They thought it was a pretty good song, though nothing that would be a huge hit.

However, Combs wanted to independently release another EP, so he recorded “Hurricane” in May 2015 along with five other songs. When he realized it would cost $200 to master each track, he could only afford to choose one. He picked “Hurricane” because it sounded the most complete. He uploaded it to iTunes via TuneCore, a third-party agency that allows anyone to sell digital tracks.

Within a week, “Hurricane” sold 15,000 copies — a shocking number for a virtually unknown artist. Combs used the money to master the rest of his EP, which led to a booking deal and then an independent label deal. In October, he signed with Columbia Nashville, as SiriusXM’s country station the Highway played “Hurricane” on a frequent rotation. It went No. 1 on terrestrial radio in May for two weeks.

Combs has the advantage of acquiring a fan base during his college years. Like his role model and fellow North Carolinian Eric Church, Combs focused on touring and earning fans before he looked for a hit. Going the opposite route, he said, “is like building an awesome company but not having any customers.”

And while he can’t articulate exactly why “Hurricane” took off, he’s grateful — and will try not to let it get in the way of writing the next good song.

“I guess I [don’t] focus too much on why they like it,” Combs said. “I’m just glad they do.”

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