BOULDER, Colo. (AP) — Authorities have released the name of a Minnesota teen who died in a Colorado hiking accident.

The Boulder County coroner said 17-year-old Carter Christensen of Maple Grove, Minnesota, died in a fall on Sunday evening in Cahutauqua Park near Boulder, which is just northwest of Denver.

The sheriff's office says Christensen was climbing alone without the use of ropes or gear when he fell, possibly more than 100 feet (30 meters), suffering "massive traumatic injuries."

Investigators say nobody witnessed the fall, but several people in the area heard it and responded to help.

Christensen posted a selfie from his climb on social media about an hour before he fell. His family released the photo.

Christensen's family said he had just graduated from high school, was visiting friends in Colorado and planned to enlist in the Navy.

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