A death at Burning Man is under investigation as rain lashes the festival and tens of thousands of people remain stranded.
Roads into and out of the event in the Nevada desert have been closed due to flooding and festivalgoers have been urged to conserve food and water and take shelter.
Police said a person has died “during this rain event” but did not provide further information. Their family has been informed.
The US Bureau of Land Management, the agency that manages the land on which the event takes place, said in a statement: “Rain over the last 24 hours has created a situation that required a full stop of vehicle movement on the playa.
“More rain is expected over the next few days and conditions are not expected to improve enough to allow vehicles to enter the playa.”
Paul Reder, who has been attending the festival for 22 years, said: “Fortunately we’re in a fairly big camp with a lot of supplies.
“As a community, everybody’s sharing with each other.”
Mr Reder said he expected it would take at least two days for the area to dry out.
While he was prepared to ride it out, he said some attendees are leaving the site on foot and trekking to the nearest motorway.
Heavy rainfall had a widespread impact across the state of Nevada on Friday, with the National Weather Service warning of flash floods up until Monday morning.
Black Rock City saw more than half an inch of rain drop overnight, organisers estimated.
Burning Man is a celebration of self-expression that culminates in the ceremonial burning of a towering 40ft effigy.
Its origins can be traced back to the incineration of an eight-foot wooden “man” on San Francisco’s Baker Beach in 1986, which eventually evolved into an annual gathering in the Black Rock Desert.
This year’s event began on 27 August and is set to continue until 4 September.