Thousands of attendees at the Burning Man festival in a remote stretch of the Black Rock Desert in Nevada were told on Saturday to conserve food, water and fuel after heavy rainfall trapped them in thick mud.

The event, which takes place in Black Rock City and began on Sunday, was interrupted by heavy rains on Friday night, and organizers directed attendees to shelter in place as rain poured over the area.

The festival site received more than half an inch of rain overnight on Friday, organizers said. While it had stopped for much of Saturday, more was expected in the evening and into Sunday morning, with a slight chance of thunderstorms, they said.

Except for emergency services, vehicles have also been prohibited around Black Rock City.

The Washoe County Sheriff’s Office said on the platform X, formerly known as Twitter, that officials had closed the entrance to Burning Man for the remainder of the event, which ends on Monday.

Festivalgoers could be trapped for several days, organizers said.

“The gate and airport in and out of Black Rock City remain closed,” organizers announced on Saturday morning. “Ingress and egress are halted until further notice.”

Black Rock City is a temporary community that pops up each year in the middle of a vast desert known as “the playa” for Burning Man. The makeshift town hosts more than 60,000 people every year and is a three-hour drive from the nearest airport, which is more than 100 miles away in Reno.

Videos on social media have shown Burning Man attendees trudging through flooded fields and dense mud. Portable restrooms, R.V. campers and people appeared to be slathered in the muck. Some tied trash bags around their shoes.

Burning Man, which has been around since the 1980s, is a self-described “community and global cultural movement” that is premised on countercultural principles, such as radical self-expression.

The festival is known to draw crowds of people dressed in eclectic garments and costumes, and it’s been popularized over the years by a steady stream of celebrity and mogul attendees.

The event features art installations and culminates with the burning of a giant sculpture of a man, giving it its name.

Tara Saylor, who is attending this year’s festival, told The Los Angeles Times, “Burning Man is radical self-reliance and we’re being put to the test.”

Despite the weather, Burning Man attendees say they were prepared and trained for such conditions. The event is “much different than going to a music festival like Coachella,” said Kaz Qamruddin, who is attending his sixth “burn.”

“We have very smart people here,” he said in a phone interview on Saturday.

People have medical supplies and warm clothes and are helping to keep others safe and dry, he said.

Attendees have also opened their R.V. campers to those who had been staying in tents, which were the most vulnerable to the water, Mr. Qamruddin said.

This year’s Burning Man has had to contend with multiple snags. On the festival’s opening day, environmental activists blockaded the entrance, creating a logjam, NBC News reported.

And with incredibly muddy conditions, water puddled to their ankles and more rain expected tonight, attendees are unlikely to leave until early next week.

Mr. Qamruddin already changed his departing flights to next Friday — after initially planning to leave on Sunday.

“This is a very kind, open, sharing, giving community,” he said. “We’re safe. I feel good.”

Colbi Edmonds contributed reporting.