You don’t often hear the crowd howling along with every lyric at a music festival. Perhaps that’s expected for headliners like A Tribe Called Quest or LCD Soundsystem, but even at an ostensibly indie-skewing event like Pitchfork Music Festival, mid-afternoon sidestage performers generally aren’t that widely beloved or even that widely known. So the outpouring of enthusiasm for Pinegrove at the Blue Stage on Sunday was startling to witness.

Kids were moshing to music that could qualify as alt-country. One person brought their vinyl copy of Cardinal into the morass of humanity up front and regularly held it high, as if flying a flag to show their allegiance. Friends — strangers? — threw their arms around each other and swayed side to side during “Aphasia.” One guy climbed a tree to get a better view during “Old Friends.” The love was palpable in a way I rarely witnessed this weekend, though as someone who considers Cardinal one of last year’s absolute best releases and who was caught up in the pandemonium myself, I may be a little bit biased here.

Frankly, even a hater couldn’t deny the Pitchfork crowd’s fervor for this band. The gospel of Pinegrove, steadily spreading for half a decade as the project evolved from a collegiate distraction to a hard-touring underground institution, has rapidly expanded its reach since Cardinal emerged 17 months ago. The album has been one of the great word-of-mouth success stories in recent indie rock history, and deservedly so: Pinegrove are one of the greatest bands in the world right now. They’ve happened upon a captivating formula, infusing Wilco-style roots rock with emo’s confessional spirit and cathartic roof-raising choruses. Evan Stephens Hall writes with a keen eye for interpersonal drama and quarter-life angst, and he manages to spin 50-cent words into melodies so contagious that on Sunday he had a field full of people screaming “ventricles” and “sublimate” right back at him.

It’s funny — a couple years ago Pitchfork wouldn’t have even booked a band that made its bones in the emo scene (whether or not they claim that mantle for themselves). But the Hotelier broke down that barrier last year in thrilling fashion, and Jeff Rosenstock delivered one of the more memorably ecstatic festival sets of this weekend, and Pinegrove whipped up the audience into fits of feverish devotion Sunday. The festival is better off for acknowledging that these bands exist.

Assuming the bands are interested in stepping into Pitchfork’s sphere of influence — not necessarily a given with artists from a DIY background — they’re better off too. Who knows how many people joined the cult of Pinegrove yesterday? Hall has tweeted that he expects the band’s next album to be out in March, and if the rhapsodic response to their old music Sunday is any kind of microcosm for the world at large, that next record is going to be huge. Perhaps someday Pinegrove will be headlining this event.