From a story on axios.com by Rebecca Falconer headlined “Historic and enduring U.S. heat wave by the numbers”:

The “dangerous, long-lived, and record-breaking” heat wave is set to continue across large portions of the U.S. West into the northern Plains and across parts of Florida, Texas and the Gulf Coast, the National Weather Service warns.

The big picture: Nearly 78 million people were under heat alerts in the U.S. Sunday evening, as health officials report a spike in callouts and Emergency Department visits due to the extreme weather.