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.

(credit: Christensen family)

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.

Full Family Statement:

“Carter was a lover of the outdoors and an adventurous spirit and was experiencing joy in summiting the First Flatiron in Chautauqua Park.

He graduated High School in June 2017 with aspirations of becoming a Navy Seal. Carter came to Colorado to be outdoors in a place that he loves. He wanted to spend some time with friends in Longmont while he trained for his Navy Seal enrollment.

Carter will be loved and missed by all of his family and friends.”

(© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)