FORT COLLINS, Colo. -- Fort Collins police are trying to identify the woman who was fell off the top of a moving car and was critically injured while attempting to "roof-surf" Monday evening.

The woman is between 18 to 20 years old, about 5 feet 5 inches tall, and 125 pounds. She has brown hair, brown eyes, and may go by the first name of Shaylynn, police said. The unidentified woman is listed in critical condition at Poudre Valley Hospital.

Police said they were called to the 600 block of Smith Street around 6:15 p.m. on the report of an accident. When they arrived, they found the victim lying in the middle of the street, bleeding from the head and barely breathing.

Witnesses told officers that the woman was attempting to stand on the roof of the moving car when she slipped and smashed her head on the pavement. A driver and a second passenger asked eyewitnesses to call 911 and then drove away in a champagne-colored four-door Buick LeSabre with Wyoming plates, police said.

Both occupants in the vehicle are described as white females, between 20 and 25 years old. One woman had blond hair but it is unknown if she was the driver or passenger, eyewitnesses said. The vehicle was last seen heading east on Laurel from Smith Street.

The victim carried no identification and has no distinguishing marks or features, hospital officials said.

Anyone with information about the the victim or this incident is asked to call Fort Collins police at (970) 221-6540.

In June, a 16-year-old girl died after a "roof surfing" in El Paso County. Roof surfing has been linked to 16 deaths nationwide since 1989, including the deaths of a 15-year-old Florida boy in November and a 10-year-old Arizona boy in May.