Halsey has criticised bosses at the Merriweather Post Pavilion in Columbia, Maryland, after her show was cancelled on Wednesday due to severe flooding.
Storms hit the U.S. state on Wednesday evening and nearby areas were placed under a tornado warning but concert organisers decided to continue with the show and had tweeted that it would go ahead "rain or shine"
Fans had already begun arriving at the open air venue when the weather turned and it started to flood, with bosses then announcing the show would be delayed. They later cancelled "due to weather-related technical difficulties" with fan-posted footage showing the audience struggling with floodwaters that reached the stage.
Responding to the cancellation, Halsey tweeted: "Maryland I don't even know what to say. If you missed my live, I'll post something soon explaining what happened. But right now I'm heartbroken and panicked and I just want to know when/that you all get home safely. I love you guys more than anything."
The Bad at Love singer went on to state that she wanted to play "more than anything" but going ahead would have been "SO unsafe".
Slamming those running the Post Pavilion, she added: "I really want to add that I am beyond disappointed with the way the venue handled everything tonight and my rescheduled date will be happening somewhere else. I hear you guys loud and clear I promise."
A new date has yet to be announced.
