SOUTH LAKE TAHOE,Slabu Calif. (AP) — A snowboarder spent 15 hours trapped overnight inside a ski lift gondola amid freezing temperatures at a Lake Tahoe resort, according to officials and media reports.

Monica Laso boarded the gondola around 5 p.m. Thursday at Heavenly Ski Resort to ride down the mountain because she was too tired to snowboard. But it stopped just minutes later while she was still in the sky, she told KCRA, which first reported the news.

Laso yelled for help, but no one on the ground heard her, the TV station reported. She didn’t have her cellphone, so she couldn’t call for help either.

“I screamed desperately until I lost my voice,” Laso told KCRA in an interview in Spanish.

She spent the night rubbing her hands and feet together to fight off the cold. The overnight low temperature was 23 degrees, according to the National Weather Service.

Laso’s friends reported her missing to the El Dorado County Sheriff’s Office on Thursday, but she wasn’t found until Friday morning when the gondola started up again for the day and crews realized she’d been there overnight, the TV station reported.

The ski resort, located on the southeastern side of the lake near the California-Nevada border, is investigating “with the utmost seriousness” how Laso got trapped.

“The safety and wellbeing of our guests is our top priority at Heavenly Mountain Resort,” said Tom Fortune, the resort’s vice president and chief operating officer, in a statement.

The sheriff’s office did not respond to a request for comment Saturday.

Kim George, a battalion chief and spokesperson for South Lake Tahoe Fire Rescue, told The Associated Press that sheriff’s deputies requested their paramedics around 8:30 a.m. Friday after Laso was discovered.

She was responsive and alert and declined to be transported to the hospital, George said.

In her 23 years with the fire department, “we’ve never responded to anything like that,” George said. “I’m very curious to hear the story.”