Brutal heat continues to plague the south-west US, with excessive heat alerts lingering long into September as parts of the region set grim new records for deaths connected to the sweltering temperatures.

Autumn has offered little reprieve for cities that have already spent months mired in triple-digit temperatures. This week, Las Vegas, Nevada; Phoenix, Arizona; and Palm Springs, California, are all grappling with severe weather, with highs that have pushed over 100F (38C). More than 16 million people in the US were under heat alerts on Friday, according to the National Weather Service, mostly clustered in the southern tips of Nevada, Arizona and California.

“Late-season heat is dangerous because people are fatigued from fighting heat all summer,” the NWS forecast office in Las Vegas cautioned in an alert, which warned of extreme weather expected to last through the weekend and into next week. “This is especially true this year,” it added, “as 2024 continues to break all-time heat records.”

Fueled by the climate crisis, and often exacerbated by concrete cityscapes that cook when temperatures rise, heatwaves are getting longer, larger and more intense…