Man and teenage stepson die on hike in Texas national park in 119F heat

More than 40 million Americans under heat alerts as temperatures across parts of US South reach triple digits

A man and his teenage stepson have died while hiking in a Texas national park as extreme heat grips the state.

The pair, who were visiting from Florida but have not been identified, were hiking on a rugged trail in Big Bend National Park in southwest Texas on Friday as temperatures reached 119 degrees Fahrenheit (48 Celsius).

They were with the boy’s older brother who attempted to carry his 14-year-old sibling back to the trailhead after he collapsed and lost consciousness.

Their 31-year-old stepfather hiked back to their vehicle to get help.

Big Bend National Park’s Communications Center received an emergency call at 6pm. A team of park rangers and US Border Patrol agents reached the scene at 7.30pm “and located the young victim deceased along the trail,” according to a statement.

Roughly 30 minutes later, the 31-year-old man was discovered dead at the scene of a car crash in a nearby embankment.

“The Marufo Vega Trail winds through extremely rugged desert and rocky cliffs within the hottest part of Big Bend National Park. No shade or water makes this strenuous trail dangerous to attempt in the heat of summer,” NPS said.

The incident is under investigation.

Big Bend – a sprawling desert park named after the large bend in the Rio Grande river that borders the US and Mexico – is experiencing extreme heat with daily temperatures reaching 110 -119F.

More than 40 million Americans are under heat alerts due to a prolonged “heat dome” which has settled above southern Texas. Highs in some parts of the states have reached 125F. “Heat domes” occur when hot ocean air fuelled by warming waters become trapped in the atmosphere.

The National Weather Service predicted temperatures will remain extremely high through the Fourth of July holiday.

The climate crisis is having a direct impact on heatwaves that scientists expect to continue as the global average temperature continues to rise. Global heating currently causes rare heatwaves to be 3 -5F warmer across most of the US, according to Climate Signals.

The US Centers for Disease Control and Prevention estimates that 702 people die from heat across the country and more than 9,000 people are hospitalised for heat-related illness each year. There are an estimated 67,512 emergency room visits due to heat annually.