A 14-year-old boy fell ill and ultimately died in extreme heat while he was hiking Saturday in Big Bend National Park in Texas, officials said.
His stepfather, identified only as a 31-year-old man, died seeking help for the boy when the vehicle he was in veered off its path and crashed down an embankment beneath an overlook, the National Park Service said in a statement.
The teenager's cause of death was pending. The local sheriff's office, where the Brewster County medical examiner is based, did not immediately respond to a request for information.
The park service said the teenager was hiking with his stepfather and an older brother, all from Florida, along the Marufo Vega Trail, near the U.S.-Mexico border, as temperatures reached 119 degrees Saturday.
Park rangers received a call for help at 6 p.m. and responded alongside U.S. Border Patrol agents, the park service said. The teen was found dead at 7:30 p.m., and the stepfather's body was found in his vehicle below Boquillas Overlook about a half-hour later, it said.
The nearest National Weather Service temperature station, an airport in Terlingua, Texas, measured a high temperature of 108 Saturday. The local weather service office issued an excessive heat warning through Tuesday that included a forecast of 120-degree highs for parts of the Rio Grande Valley.
The older brother, identified as a 21-year-old man, was unharmed, the park service said. He had tried to carry the teenager back to the trailhead, it said.
On Sunday, the park service said temperatures were "deadly" and recommended that visitors avoid hiking along the Marufo Vega Trail in the afternoon.
"The Marufo Vega Trail winds through extremely rugged desert and rocky cliffs within the hottest part of Big Bend National Park," the park service said. "No shade or water makes this strenuous trail dangerous to attempt in the heat of summer."
The deaths were under investigation, the park service said.