Thousands of attendees of this year's Burning Man festival are stuck in the Nevada desert after heavy rains turned the desert site into mud on Saturday. Local authorities said they are investigating a death during the event.

The deceased person's identity or the cause of death remains unknown.

Meanwhile, the U.S. Bureau of Land Management has temporally closed off access to and from the event site in Black Rock City, expecting further rainfall.

"More rain is expected over the next few days, and conditions are not expected to improve enough to allow vehicles to enter the playa," the bureau said.

The festival's organizers urged people already on site to "conserve food, water and fuel, and shelter in a warm, safe space."

All vehicular traffic on the sprawling festival grounds has ceased, leaving portable toilets unable to be serviced.

The Burning Man festival is a famous arts and culture event held in the Black Rock Desert, which is usually dry and dusty. Attendees build a temporary city in the middle of the desert and are expected to be largely self-sufficient while they are there.

More than 70,000 people had arrived at the site before it was closed on Saturday, local media reported.

Over 3.8 centimeters of rain is believed to have fallen at the festival site on Friday, the National Weather Service said.

This year's event was scheduled to run from August 27 to September 4.

(With input from agencies)