The woman faces up to five years in prison when she is sentenced on Sept. 24.
The stabbing allegedly took place about 1:30 a.m. on June 23. Forest rangers alerted the Wasatch County Sheriff's office of a disturbance after they heard someone scream, "I will [expletive deleted] kill you," from within the grounds of the Rainbow Gathering.
According to court records, Novak-Garcia had been repeatedly honking her horn for about a half-hour when 45-year-old Neil Sparling asked her to stop. He told police that when he tried to remove the fuses from underneath the hood of the car to disable the horn, he was stabbed in the head and shoulder.
During the same episode, Novak-Garcia allegedly stabbed another man in the arm.
Another man also was allegedly hit with a tire iron, but the alleged victim was never found, according to prosecutors.
The man who was stabbed in the arm "believed that Leilani's conduct on the night in question was out of character for her and was probably the result of 'taking some bad drugs,' " a Wasatch County Sheriff's detective wrote in a document seeking a material witness warrant.
The U.S. Forest Service estimated that nearly 8,000 people flooded the national forest outside of Heber City for this year's Rainbow Gathering. The annual event is intended to promote peace and communion with nature.