A woman hiking down the South Kaibab Trail for a night at Phantom Ranch, seen below from the trail, collapsed and died/NPS file

Triple-digit heat in the Inner Gorge of Grand Canyon National Park is believed to have played a role in the death of a California woman planning to spend the night at Phantom Ranch along the Colorado River.

Catherine Houe, 49, of Daly City, had hiked about 4 miles down the South Kaibab Trail with her husband and a friend when she became "dizzy, disoriented, and then stopped breathing," a park release said Friday morning.

The trio was about two-thirds of the way down the trail to Phantom Ranch when Houe collapsed around 5:30 p.m. Wednesday not far above the Tip Off resthouse, the release said.

Rangers flew down from the South Rim via helicopter while CPR was being administered to the woman.

An investigation into the incident was being conducted by the National Park Service in coordination with the Coconino County Medical Examiner's Office. No additional information is available at this time.

The woman was about a half-mile from the Tipoff Resthouse on the South Kaibab Trail when she collapsed/NPS, Michael Quinn

There has been extreme heat at the Grand Canyon this week, and rangers have strongly urged visitors, especially inner canyon hikers and backpackers, to be prepared for excessively hot days in the coming weeks. In the summer, temperatures on exposed parts of the trail can reach over 120° F (49° C) in the shade. Hiking in extreme heat can lead to serious health risks including heat exhaustion, heat stroke, hyponatremia, and death.

The high temperature at Phantom Ranch on Wednesday was 114 degrees Fahrenheit.