A Petaluma woman who was in the South Lake Tahoe area for a music festival has been missing since New Year's Eve, her family said.

Alyssa Byrne, 19, was last seen at about 12:30 a.m. Tuesday by friends at the Horizon Casino Resort in Stateline, Nev., Douglas County sheriff's officials said in a statement.

Byrne had been in the area since Saturday for the SnowGlobe Music Festival on the Lake Tahoe Community College campus in South Lake Tahoe, said her mother, Kim Miller-Byrne of Petaluma.

Byrne took a shuttle from the concert to the casino-resort about 4 miles away in Stateline. But Byrne didn't return to the shared room and didn't show up for a ride home the next day, Miller-Byrne said.

"They called the hospitals, the police, the sheriff's department, and they couldn't find her," Miller-Byrne said.

Byrne's friends filed a missing-person report with South Lake Tahoe police, and police handed the case to the Douglas County Sheriff's Office in neighboring Nevada.

Between Saturday and Monday, she had touched base with her family each day, they said.

"She doesn't do this at all, and she's very reliable," Miller-Byrne said. "She was texting (with me) every day."

Byrne's cellphone was last used Monday in the city of South Lake Tahoe, according to a Sheriff's Office statement.

Surveillance images at the casino didn't offer police any clues, according to Miller-Byrne.

Byrne graduated from Casa Grande High School in 2011.

She works as a hostess at Cattlemen's restaurant in Petaluma and is taking classes at the Santa Rosa Junior College Petaluma campus to become a paramedic-firefighter.

Byrne's father, Kevin Byrne, was in South Lake Tahoe. A group of fellow Casa Grande alums drove up Wednesday to join him and help pass out fliers and look for her, Miller-Byrne said.

Byrne was described as 5-foot-3, about 125 pounds, with blue eyes, long hair dyed black and a fair complexion.

Anyone with information about Byrne can call the Douglas County Sheriff's Office dispatch at (775) 782-5126 or Investigator Dennis Slater at (775) 586-7255.

You can reach Staff Writer Julie Johnson at 521-5220, julie.johnson@pressdemocrat.com or on Twitter @jjpressdem.