By Scott Sonner, Associated PressRENO, Nev. (AP) — Authorities said Monday that they are investigating the death of a woman at the counterculture festival known as Burning Man, which is held annually in the northern Nevada desert.The Pershing County Sheriff's Office said emergency personnel responded to a call about a woman found unresponsive around noon Sunday in Black Rock City — a temporary city erected for the festival, about 100 miles (160 kilometers) north of Reno.The Burning Man Project's emergency services personnel were unsuccessful in attempted life-saving measures on the woman."Our thoughts and condolences go out to the family and friends affected by this loss," festival organizers said in a statement. "We are cooperating fully with local authorities as they investigate this incident."About a half-dozen other deaths have been reported at the festival since it moved from Baker Beach in San Francisco to the Black Rock desert in 1990. Last year, a 32-year-old California man died from suspected drug intoxication after being found unresponsive on the festival grounds.Pershing County Sheriff Jerry Allen said in a statement that Sunday's death will remain under investigation until a cause and manner can be determined, which will be updated at the conclusion of an autopsy.A call to the Washoe County Regional Medical Examiner's Office wasn't immediately returned Monday.Allen said the woman's name and age won't be released until her relatives can be notified.The festival, which combines wilderness camping with a weeklong celebration of art for art's sake, kicked off early Sunday after the gates had been closed for 12 hours following rain and muddy conditions.An estimated 20,000 people were already on the playa before the gates officially opened to all ticket-holders.Burning Man runs through Sept. 2 . Organizers expect more than 70,000 people to attend this year's event.Known for its colorful theme camps, towering sculptures, drum circles, art cars and avant-garde theatrics, it grew from a gathering of about 4,000 in 1995 to 50,000 in 2010 and now temporarily becomes Nevada's third-largest city after metropolitan Las Vegas and Reno.In 2023, the 35th annual Burning Man festival was attended by an estimated 73,000 people with an additional 95,000 participating in regional events around the world.It was disrupted by a protest blockade that was shut down by local authorities and about a half inch (about 1.3 centimeters) of rain turned the playa into mud, making it difficult to drive and pedal bicycles.Authorities brought in cell towers and asked attendees to stay put until the rain cleared.Other deaths recorded at Burning Man over the years included a woman who was hit by a bus in 2014 and an attendee who fell under a trailer in 2007. In 1996, a friend of Burning Man co-founder Larry Harvey was killed in a collision with a van while riding his motorcycle at night.First published by The Nevada Independent.