Despite best efforts by rangers who covered more than 5 miles in less than two hours, a Boulder, Colorado, woman died after falling 25-50 feet into a creek near Odessa Lake in Rocky Mountain National Park.

The 62-year-old woman, who was not identified, fell about 12:30 p.m. Friday, according to park officials. Initial reports were received by park dispatch around 1 p.m., but were not entirely clear where along the Fern Lake Trail the accident occurred.

A hasty team of two rangers left the Fern Lake Trailhead at 1:56 p.m. and covered 5.5 miles in less than two hours, reaching the woman at 3:41 p.m. It is unclear how long the victim was in the water, but when the rangers arrived they found her hypothermic and her level of consciousness had decreased. As other rangers began to arrive on scene, CPR was initiated and performed at 4:56 p.m. for over an hour.

Cardiac medications were administered and an Automated External Defibrillator (AED) was used but to no avail. The woman was pronounced dead at 5:56 p.m. The Larimer County Coroner’s office will determine cause of death.