US heatwave: At least 14 dead in southern states

Heat index levels of up to 44°C forecast for parts of Florida over next few days

Tubers float along the Comal River in New Braunfels, Texas, as the state battles a heatwave. AP

Dangerous heat and humidity continued to affect parts of the South and Midwest on Friday, killing at least 14, with extremely high temperatures expected to linger for the Fourth of July holiday weekend.

High levels of heat put pressure on the Texas power grid and killed 13 people there as well as another in Louisiana. The heatwave pushed eastward on Thursday and was expected to be centred over the mid-South by the weekend.

Heat index levels of up to 44°C were forecast for parts of Florida over the next few days.

Eleven of the heat-related deaths in Texas occurred in Webb County, which includes Laredo. The dead ranged in age from 60 to 80 years old, and many had other health conditions, according to the county medical examiner.

The other two fatalities were Florida residents who died while hiking in extreme heat at Texas's Big Bend National Park.

Scientists and medical experts say deaths caused by extreme heat will only increase in the US each summer without more action to combat climate change that has pushed up temperatures, making people especially vulnerable in areas unaccustomed to warm weather.

Extreme heat is already the deadliest of all weather events in the US, including hurricanes, tornadoes, wildfires and flooding.

“Heatwaves are the deadliest because they affect such large areas and can go on for days or weeks,” Joellen Russell, a climate scientist who teaches at the University of Arizona in Tucson and is currently on a Fulbright scholarship in Wellington, New Zealand, told the Associated Press.

“And they catch people by surprise.”

The National Weather Service issued an excessive heat warning for parts of Arkansas, Louisiana, Mississippi and Tennessee for Friday.

Less urgent heat advisories covered a wider area that included parts of Missouri, Kansas, Kentucky, Indiana and Illinois.

The heat index, which indicates how hot it feels outdoors based on the temperature and relative humidity, was expected to reach 46°C in several cities.