Inside the scramble to save lives as heat menaces two Southwestern counties

LAS VEGAS — As temperatures began to rise in Phoenix this spring, Dr.

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.

But Maricopa County — the most populous county in the desert Southwest — has invested heavily in heat preparedness planning and mitigation. Multiple cooling centers in Phoenix now stay open 24/7. The county boosted public messaging about heat safety and hired a full-time heat relief coordinator.

As a result, it recorded fewer heat deaths last year than the year before, despite record-breaking heat — its first such dip in a decade. Now that summer is over, officials are evaluating this year’s progress, and preliminary data indicates the downward trend will continue: Maricopa County has confirmed 185 heat deaths so far, significantly less than the 284 at the same time last year.