The video above is from a previous report.
Big Bend National Park's Communications Center responded to a body found at about 7:45 p.m. along the Chimneys Trail. Upon arrival, rangers said they found the 75-year-old man, identified as Issac Irving Rosen, about half a mile from where the trail began.
The Chimneys Trail is a 5-mile round trip described as a moderately difficult hike that travels to volcano formation in the western desert of the park.
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Investigators said there is no obvious cause of death.
"Big Bend National Park staff and partners are saddened by this loss," Deputy Superintendent David Elkowitz said. "Our entire park family extends sincere condolences to the hiker's family and friends."
Temperatures at Big Bend typically reach over 100 degrees by the late morning and increase to hazardous levels long after sunset. On Thursday afternoon, the temps along Chimneys Trail exceeded over 104 degrees.
Park Rangers are reminding visitors to be aware of the dangers of the severe heat, and those who plan to hike should prepare to drink and carry one gallon of water per day and plan to be off the trails by noon.