DULUTH — A college student found unconscious outside a neighbor’s house in Duluth had been outside in subzero temperatures for more than nine hours and suffered severe hypothermia, according to police.

Alyssa Lommel, 19, a University of Minnesota Duluth student, had been out drinking with friends Friday night and was dropped off at her house around midnight, according to a police report. A passer-by, Ellen Johnson, spotted Lommel on the front stoop of the house about 9:30 a.m. Saturday as she and her boyfriend drove by.

“I was surprised nobody had seen her,” Johnson said. “It was hard to miss her.”

The couple called 911 and emergency crews arrived quickly. Johnson, who is a lifeguard, said she has had to help people in trauma before but has “never seen anyone look like that.”

The male driver who dropped Lommel off at her house told police she was walking and talking and didn’t appear extremely intoxicated, according to the police report.

Police investigators followed Lommel’s tracks in the snow. Some led to a garage, leading them to think she might have sought refuge there for a while. Tracks also circled a locked car in the backyard. She also walked down a dead-end street before coming back to the home.

The police report says some tracks between the two homes show she probably used the side of a home to stand up. Other tracks show an area where she probably fell. Police believe she climbed over a railing to the steps where she was later found. Authorities found her cellphone on a back deck.

Lommel’s mother, Teri, posted on the family’s CaringBridge website Tuesday that her daughter “had several procedures done today that will hopefully help her on her healing path.”

Lommel’s medical team has been testing the circulation in her limbs, the family wrote, and working to reduce swelling.

The family wrote earlier that Lommel was in a “comfortable state” after surgery to restore blood flow in an arm. She has been heavily sedated and the family hasn’t been able to learn how she ended up outside on the steps of her neighbor’s home.