SPRINGDALE, Utah (AP) — A woman died and a man was rescued and treated for hypothermia after they were caught in extreme cold weather while hiking in Utah’s Zion National Park, officials said.

The married couple were on a permitted, 16-mile (25-kilometer) hike through the park area known as the Narrows, the National Park Service said in a statement Thursday.

The woman, 31, and the man, 33, were not identified by the park service.

The Zion National Park Search and Rescue Team responded on Wednesday morning after shuttle drivers said visitors reported an injured man and a non-responsive woman in the Narrows, the park service said.

The rescue team found the man on a trail being helped by other hikers and transported him to the Zion Emergency Operations Center for treatment. Rescuers moved further up the Narrows and found the woman near the Virgin River. They administered emergency aid but determined the woman had died, the park service said.

The couple started their trip through the Narrows on Tuesday. The pair stopped about 1.5 miles (2.4 kilometers) from the north end of Riverside Walk, a paved trail. The man told rescuers they became “dangerously cold” overnight and experienced symptoms consistent with hypothermia, the park service said.

Early on Wednesday morning, the man sought help and the woman remained in place. Other visitors administered CPR to the woman before the rescue team arrived, the park service said.

The Washington County Sheriff’s Office, Utah Office of the Medical Examiner and the park service are investigating the cause of the woman’s death.