The park says 54-year-old Richard Merrill of Friendswood died while hiking on the Marufo Vega Trail on Tuesday.
According to a press release posted on the park's Facebook page, park rangers stopped to investigate a vehicle parked at the trailhead and found a note with Merrill's plan to hike from 7 a.m. to 2 p.m., with a request to notify the park if he hadn't returned by then.
Rangers began their search the next morning and found Merrill's body about a quarter mile off the trail near the junction of the Strawhouse and Marufo Vega trails.
"We are deeply saddened by this loss and would like to extend our sincere condolences to the friends and family of Mr. Merrill," said Big Bend National Park superintendent Bob Krumenaker.
A fellow hiker who knew Merrill as an experienced outdoorsman who had been visiting Big Bend National Park since his childhood, often several times a year, was stunned by Merrill's death.
"Marufo Vega is a tough trail in a very harsh environment," he told ABC13. "I can't imagine why he went in July, and then, why he didn't begin his hike at 5 a.m. Richard was intelligent, cautious, and conservative, definitely not one to take unnecessary risks."
The park says that morning, temperatures in the area were in the 90s and reached 106 degrees by late afternoon.
"The environment of Big Bend in the summer is, sadly, unforgiving," continued Krumenaker. "We urge all hikers to be sure they are prepared for the summer desert conditions so they are able to return home and safely visit Big Bend again."
The park is reminding visitors that hiking in the desert in the summer can be dangerous.
They recommend hiking only in the early morning hours, and to get off all trails by the time temperatures reach 95 degrees, which they say is typically between 10 a.m. and 11 a.m. in the summer.
Merrill was a proud alum of the University of Texas, a musician and active in his church.