The death of a California woman walking on a trail in the Grand Canyon National Park last week has been linked to the heat as temperatures rose to more than 100 degrees, according to authorities.
The National Park Service (NPS) said in a press release that Catherine Houe, 49, of Daly City, California, entered the canyon late Wednesday afternoon to spend the night in Phantom Ranch.
Officials received a call around 5:36 p.m. from someone reporting a fatality on the South Kaibab Trail, approximately half a mile from the Alert Ward.
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Houe had walked four miles on the South Kaibab Trail when she reportedly got dizzy, disoriented, and then stopped breathing, according to her husband and friend.
CPR was started and NPS personnel responded from the south edge with a helicopter, but the 49-year-old man was pronounced dead at the scene.
Park officials said Wednesday that the high temperature at Phantom Rance was 114 degrees Fahrenheit.
"The cause of death is believed to be related to heat," said the NPS.
Authorities said the National Park Service is conducting an investigation into the incident in coordination with the Coconino County Medical Examiner's Office.
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National Park Rangers urge visitors to the Grand Canyon National Park to be prepared for "excessively hot days" in the coming weeks, especially those hikers heading to the inner canyon.
In the summer, temperatures on the exposed parts of the trail can reach over 120 degrees F in the shade.
"Walking in extremely hot conditions can lead to serious health risks, such as heat exhaustion, heat stroke, hyponatremia and death," authorities said.
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Before death, the NPS had issued another warning about "unforgiving" conditions in the canyon by publishing a photo of a worn hiking book that had separated from its plant due to heat.
"The heat inside the barrel can cause the shoes to separate, and heavy hiking boots can trap sweat and cause painful blisters," park rangers said. "Before you start a hike, understand the limitations of you and your team."
Janine Puhak of Fox News contributed to this report.