It had looked like clear skies earlier Wednesday, a perfect day for an outdoor concert. Halsey had been scheduled to perform at Merriweather Post Pavilion, a large outdoor venue in Columbia, Maryland.
Instead, unexpected torrential downpours flooded the partially covered amphitheater, leaving fans wading through filthy, ankle-deep water until the show was finally canceled.
Halsey never wound up taking the stage, and later said in a tweet they were "heartbroken and panicked" by the ordeal but called off the performance over safety concerns.
Photos and videos of the chaotic scene have flooded (lol, sorry) social media, with attendees sharing their tales of how it devolved into such a mess.
"Water came rushing through the amphitheater," Staci Downing, 26, told BuzzFeed News. "Water bottles, beer bottles, chicken tenders, you name it, came flooding down the steps into the pit."
The first opener's set was cut short due to the storm, but venue staff reassured the crowd that the concert would continue. Meanwhile, people's phones were lighting up with emergency alerts warning of flash floods and thunderstorms.
Shortly before 9 p.m., many received tornado warning alerts. Still, the event was not called off, and staff directed attendees to take shelter, either by staying in the venue or going to their cars or a bathroom.
"Then the flooding started," Anna Johns, 26, told BuzzFeed News. "At first I heard people screaming, and turned around to see what was pretty much a waterfall cascading onto the seating area of the pavilion — just like a constant stream of water."
Water poured in through the roof, flooding the general admission pit and leaving fans standing in dirty, trash-filled pools. Even those higher up, in the seated area, couldn't avoid getting soaked. "If I wouldn’t have picked up my feet to stand on my chair and on the railing, there probably would have been water up to my ankles," said another attendee, Ben Kelkis.
One viral video showed a rain-drenched squirrel scampering across the stage before a man punted it off and into the water.
"It's a squirrel!!! It's a squirrel!" one attendee can be heard yelling in the video. "His name is Chuck — we're naming the squirrel Chuck."
Finally, around 10 p.m., a staff member announced that the show was being called off. "Everyone started immediately booing the person onstage and a majority of people left," Gabby Frost said.
In a statement posted to Twitter, the venue said the storm had "struck more intensely and lasted longer than anticipated."
"It was everyone's sincere hope that the show would go on, but ultimately the decision was made to cancel the show," it said.
Halsey expressed disappointment "with the way the venue handled everything" and said in a tweet that a rescheduled show would be held elsewhere.