“I got excited,” she told me. “And then I got worried.”

So did much of southern Nevada. This past week, Lincoln and Nye Counties issued declarations of emergency in preparation for the crush of humanity expected to descend on the area on September 20. More than a half-dozen local, state, and federal agencies are involved in the planning, including the Las Vegas Police, the Nevada Department of Public Safety, and the state highway patrol. Governor Steve Sisolak’s office has been briefed and is monitoring the situation. And when the alien enthusiasts arrive, 200 to 300 police officers, medics, and firefighters will be on hand to receive them.

“We have been nonstop preparing for the past few weeks,” said Lincoln County Sheriff Kerry Lee, who has been convening daily with county officials and weekly by phone with the state’s Department of Public Safety. Even the FBI has gotten involved, he told me.

Lee, a friendly man with a thick mustache, has seen plenty of Area 51 trespassers in his day; apprehending them is just part of his job. Most months, three or four cross the boundary—a remarkable rate, given that trespassers usually face a $1,000 fine and up to six months in prison. Once, Lee stopped a bus carrying 17 people. But the past month has been unlike anything he’d seen before.

Read: The government now admits there’s an ‘Area 51’

By mid-August, more than a month before the event, visitor traffic had already spiked 1,700 percent. And while most of those out-of-towners have come just to look around, some are more enterprising: A few weekends ago, police apprehended seven trespassers in the space of 24 hours. The Alien Research Center, meanwhile, has had almost 20 times as many daily visitors as it did a few months ago. Usually, Looney said, she can go an entire day without seeing 50 visitors; now she sometimes counts 50 at the same time.

These visitors, the emergency planners think, are only the advance guard. Based on social-media monitoring, on-the-ground observations, and motel and rental-car reservations, officials are anticipating that roughly 30,000 people will show up on September 20, says Varlin Higbee, vice chair of the Lincoln County Board of Commissioners.

So far, Lincoln County has sanctioned two events for the weekend of the supposed storming. One, featuring a lineup of prominent ufologists, will be hosted by the Alien Research Center in Hiko. The other, dubbed Alienstock, will be hosted by the Little A’Le’Inn in nearby Rachel and will take the form of a more standard EDM festival (“celebrating aliens,” of course).

If it seems like the two events are walking a fine line between encouraging good clean (conspiracy-theory-fueled) fun and endorsing a massive act of (also conspiracy-theory-fueled) criminal trespassing, that’s because they are. The Hiko event warns on its website, “There will be no misguided ‘storming’ of an active military installation that defends our national security.” But its title—“Storm Area 51 Basecamp: Get Abducted at Your Own Risk”—does send a confusing signal. The Alienstock organizers have eschewed mixed messaging in favor of no messaging; the word storm cannot be found on their website at all.