Hundreds of family members and friends attended a vigil Friday night in Petaluma for Alyssa Byrne.
Two public utility workers found the 19-year-old's body in South Lake Tahoe, not far from the music festival she attended, and where she was last seen.
Her cause of death has not yet been determined, but police do not suspect foul play or suicide.
Investigators believe Byrne may have been trying to walk from the music festival back to her hotel, and got disoriented or lost.
Nighttime temperatures have plunged to zero in the area in the past week, with daytime highs still well below freezing.
"If exposed to the elements you could succumb to that," Douglas County Undersheriff Paul Howell told The Associated Press. "We won't speculate on that (hypothermia) as the cause of death, but we're hoping to get an answer from the autopsy."
The autopsy also will determine whether alcohol or drugs were a factor, he said.
The Associated Press contributed to this report.
