BIG BEND NATIONAL PARK, Texas (KXAN) — A Houston man was found dead on a trail in Big Bend National Park Thursday evening.

The body of the 75-year-old man was found along the Chimneys Trail, about a half-mile from the trailhead. There was no obvious cause of death, the park said. The temperature was above 104 degrees on Thursday afternoon.

The Chimneys Trail is considered moderately-difficult, the park said. It’s a five-mile round trip hike with a series of volcanic formations in the western desert of the park.

“Big Bend National Park staff and partners are saddened by this loss,” said Deputy Superintendent David Elkowitz in a news release, “and our entire park family extends sincere condolences to the hiker’s family and friends.”

The park reminds visitors the hot weather in Big Bend is extreme. Temperatures for much of the area reach over 100 degrees by the late morning and increase and stay at dangerous levels long after sunset.

The park said hikers should carry and drink one gallon of water per day and plan to be off desert trails by noon.