RENO, Nevada (AP) — Authorities in Nevada were investigating a death at the site of the Burning Man festival where thousands of attendees remained stranded Saturday night as flooding from storms swept through the Nevada desert.

Organisers closed vehicular access to the counterculture festival and attendees trudged through mud, many barefoot or wearing plastic bags on their feet. The revelers were urged to shelter in place and conserve food, water and other supplies.

The Pershing County Sheriff’s Office said the death happened during the event but offered few details as the investigation continued, including the identity of the deceased person or the suspected cause of death, KNSD-TV reported.

On their website, organisers encouraged participants to remain calm and suggest that the festival is built to endure conditions like the flooding. They said cellphone trailers were being dropped in several locations Saturday night and that they would be briefly opening up internet overnight. Shuttle buses were also being organised to take attendees to Reno from the nearest town of Gerlach, a walk of about five miles (eight kilometres) from the site.

“Burning Man is a community of people who are prepared to support one another. We have come here knowing this is a place where we bring everything we need to survive,” the organisers said in a statement. “It is because of this that we are all well-prepared for a weather event like this.”

Celebrity DJ Diplo posted a video to Instagram on Saturday evening showing him and comedian Chris Rock riding in the back of a fan’s pickup truck. He said they had walked six miles through the mud before hitching a ride.

“I legit walked the side of the road for hours with my thumb out,” wrote Diplo, whose real name is Thomas Wesley Pentz.

Vehicle gates will not open for the remainder of the event, which began on August 27 and was scheduled to end Monday, according to the US Bureau of Land Management, which oversees the Black Rock Desert where the festival is being held.

More than one-half inch of rain is believed to have fallen on Friday at the festival site, located about 110 miles (177 kilometres) north of Reno, the National Weather Service in Reno said. At least another quarter of an inch of rain is expected Sunday.

The Reno Gazette Journal reported organisers started rationing ice sales and that all vehicle traffic at the sprawling festival grounds had been stopped, leaving portable toilets unable to be serviced.

Officials said late Saturday the entrance to the event remained closed, and it wasn’t immediately known when celebrants could leave the grounds. No driving is allowed except for emergency vehicles and organisers said they didn’t have a time yet when the roads would “be dry enough for RVs or vehicles to navigate safely.” But if weather conditions improve, they were hopeful vehicles could depart by late Monday.

The announcements came just before the culminating moment for the annual event — when a large wooden effigy was to be burned Saturday night.

Messages left Saturday afternoon by The Associated Press for both the Bureau of Land Management and the Pershing County Sheriff’s Office, the agencies that closed the entrance, weren’t immediately returned.

Many people played beer pong, danced and splashed in standing water, the Gazette Journal said. Mike Jed, a festivalgoer, and fellow campers made a bucket toilet so people didn’t have to trudge as often through the mud to reach the portable toilets.

“If it really turns into a disaster, well, no one is going to have sympathy for us,” Jed said. “I mean, it’s Burning Man.”