LAS VEGAS — As temperatures began to rise in Phoenix this spring, Dr. Jeffrey Johnston braced for the many hundreds of deaths that have become a grim summer trend.
Johnston, the chief medical examiner for Maricopa County, Arizona, has seen extreme heat kill more and more people over the last decade: Heat-related fatalities there jumped from several dozen in 2014 to 645 in 2023.
“The surges were so intense and long, so we really did approach it like a mass casualty event,” he said of recent summers…