Cleaning up after the Burning Man festival is serious business.

By Adam Mandelman 

Every year, in the weeks leading up to Labor Day, a temporary metropolis emerges from the barren alkali flats of Nevada’s Black Rock Desert. Meticulously surveyed, the concentric circles and spokes of Black Rock City’s dusty streets fan out across some seven square miles of dry lake bed (or “playa”), providing an iconic geography for one of North America’s more bizarre annual rituals: Burning Man.

But the chaotic arts and music festival, known for its high hedonism, is as much an exercise in evanescent urban planning as it is a radical social experiment. Come Labor Day, Burning Man’s deeply ingrained leave-no-trace ethos takes over. Attendees pack up gear, artists break down installations, and theme camps dismantle projects so elaborate that one wonders whether Burning Man is actually an engineering fair. Show up to the event a month late, and you’ll be hard-pressed to find any trace of the booming city of 70,000 that once sprawled across the desert. Gone are the flame-throwing mechanical octopus, the enormous Dr. Bronner’s foam dome, and the countless 75,000-watt sound systems pumping bass across the arid playa.

“It’s the mythological city that suddenly springs forth before disappearing into nothingness…. It’s the biggest flash mob on the planet,” says Dominic “D.A.” Tinio, Burning Man’s manager of playa restoration. Known uninspiringly as “cleanup” until 2004, playa restoration is arguably the single most important duty of the festival’s Department of Public Works (or DPW). DPW volunteers typically look as if they stepped off the set of Mad Max and can spend up to three months in the desert, first building and then erasing Burning Man. Whatever might be said of the feats of planning and engineering that go into building Black Rock City—one theme camp plans to haul a grounded Boeing 747 to the desert in 2016—playa restoration is perhaps the most impressive. Making a beautiful mess on a canvas as starkly empty as Black Rock Desert is comparatively easy. Restoring that canvas to blankness on the other hand? Not so much.

Black Rock Desert is part of a broad swath of public lands in Nevada administered by the U.S. Bureau of Land Management (BLM). Everything that participants bring to and produce on the playa—from stray sequins to dishwater, piles of wood chips to human waste—has to be removed according to the festival’s special recreation permit with the BLM. For Burning Man to pass its annual leave-no-trace inspection, the DPW’s playa restoration crew has to ensure that less than one square foot of impact per acre remains in the festival’s 4,400-acre event area. Given the scale and intensity of the event, that would seem an impossibly daunting challenge. If the 120 or so volunteers conducting playa restoration were responsible for the trash and graywater of 70,000 Burners—let alone the remains of things like flaming piano projectiles—Burning Man would be doomed to fail its inspections.

Which is where “moop” comes in. Somewhere in the evolution of Burning Man, festivalgoers incorporated an artifact of 1960s cultural anthropology deep into Burner culture. Moop stands for “matter out of place,” and, as far as anyone can tell, first originated with the British anthropologist Mary Douglas and her 1966 book Purity and Danger. Douglas argued that despite what seem to be universal human reactions to uncleanliness, concepts like filth and pollution actually depend on context. “Dirt” is just matter out of place. Raw chicken, for example, is fine in the kitchen, but acutely disgusting on the dinner table.

Over the years, “matter out of place” at Burning Man has mutated from an all-caps acronym—MOOP—into a noun and two different verbs (“to moop” is both to make a mess and clean it up). Moop became such a core element of the Burner lexicon for good reason. In the parched expanses of the Black Rock Desert, pretty much everything except alkaline dust will be moop if it gets left behind. Every single errant feather or tent stake, every last abandoned couch or bicycle becomes moop the moment someone ceases to be responsible for packing it off the playa. Since leaving no trace is both a condition of the festival’s survival and one of the “10 Principles” of Burner culture, attendees are encouraged to put as much energy into cleaning up as they do into experiencing the event. Everyone moops, so to speak.

DPW’s playa restoration crew thus represents the last phase of cleanup after Burning Man. Instead of hauling away the refuse of an entire city, DPW is focused more on either easily overlooked or particularly troublesome instances of “dirt” on the playa: wood chips, nails and staples, cinders, oil slicks, burn scars, and so on. Since 2006, Tinio and his crew have plotted their labors using GPS data to produce the annual Moop Map, a leave-no-trace report card markedly successful at further motivating festivalgoers to help restore Black Rock Desert’s purity.

“Maps tell stories” is a favorite aphorism among geographers, and the Moop Map is no exception. Thanks to the culture of moop, Burning Man—despite its storied excesses—has never failed a BLM inspection. In fact, according to the BLM project manager David Freiberg, the festival “sets the leave-no-trace standard bureau-wide for special recreation permits.” Here in the austere wilderness of an ancient lake bed, tens of thousands of human beings manage to erect and completely erase a spectacular city in just a matter of weeks.

If Burning Man is the planet’s biggest flash mob and largest leave-no-trace event, then it’s also the world’s most transitory city. That essential transience brings to mind Tibetan sand mandalas—complex patterns of painstakingly arranged colored dust that are swept away at the moment of completion. Call it Buddhist Urbanism, if you will. After all, for Tinio, leave no trace is “the secret meaning of Burning Man.”

Adam Mandelman is a geographer and environmental historian. He is working on a book about three centuries of environmental change in the Mississippi River Delta.