It's still unclear how a young woman ended up unconscious on her neighbor's porch in Duluth, Minn. Friday night, spending more than nine hours in temperatures that dropped to 17 below zero.

University of Minnesota-Duluth student Alyssa Lommel, 19, is reportedly stable but in critical condition at Regions Hospital in St. Paul. Because she is heavily sedated, she hasn't yet been able to explain what happened, according to the Associated Press.

She was dropped off around midnight Friday after spending the night with friends, according to the AP. She didn't have gloves or a heavy jacket, and was found by passersby around 9:30 a.m. Saturday, the St. Cloud Times reported.

"I was surprised nobody had seen her," Ellen Johnson, one of the passersby, told the AP. "It was hard to miss her."

According to the police report, Lommel was breathing shallowly and her hands were swollen when she was found, the St. Cloud Times reported. Her parents said her hands and feet were damaged in the cold.

On a CaringBridge site, Lommel's family wrote that doctors are testing her circulation and trying to reduce swelling, the AP reported. 

The Duluth News Tribune reported that police haven't said whether alcohol was involved in the incident, though noted that Lommel tweeted Friday about taking tequila shots. But according to the police report, the driver who dropped her off said she didn't appear extremely intoxicated, the AP reported.