LAS VEGAS — As temperatures began rising in Phoenix this spring, Dr. Jeffrey Johnston braced himself for the many hundreds of deaths that have become a grim summer trend.
Johnston, the chief medical examiner for Maricopa County, Arizona, notes that more and more people have died from extreme heat over the past decade, with the number of heat-related deaths jumping from a few dozen in 2014 to 645 in 2023.
“The surges were so intense and long lasting that we really approached this as a mass casualty event,” he said. recent summer.
But Maricopa County, the most populous county in the desert southwest, has invested heavily in planning for heat preparedness and mitigation. Several cooling centers in Phoenix are now open 24/7. The district has increased public education about heat safety and hired a full-time heat assistance coordinator.
As a result, fewer heat-related deaths were reported last year than the year before, despite record heat – the first such decline in a decade. Now that summer is over, officials are assessing this year's progress, and preliminary data suggests the downward trend will continue: There are now 185 heat-related deaths confirmed in Maricopa County, down significantly from the 284 at the same time last year.
A different story played out in Clark County, Nevada, the second most populous region where Las Vegas is located. Heat-related deaths here have more than tripled in just three years, with a record 513 people killed in 2024. The death toll for this year is still preliminary, but the heat death toll is likely to be in the hundreds.
Ariel Choinard, a scientist at the Desert Research Institute in Las Vegas, said last summer's brutal temperatures were a major warning sign.
“There was something about seeing 120 degrees in Las Vegas that made people go, 'Oh my gosh, wait, this is really serious,'” she said.
Scheunar is at the forefront of local efforts to prevent heat-related deaths in Clark County and is monitoring the progress being made in Maricopa County. She knows she needs to catch up.
“They started heating earlier than we did in this region, so in many ways they are ahead of us,” she said.
Heat kills more people in the United States each year than any other type of weather event, including hurricanes, floods and tornadoes. according to the National Weather Service. As climate change increases the frequency and intensity of heat waves, these two counties in one of the fastest-warming parts of the U.S. could serve as a cautionary tale about what it will take to save lives in the face of this growing threat—and the serious loss of life due to inaction.
“Every one of these deaths is preventable.”
Heat tends to kill differently. Particularly vulnerable are people who do not have access to air conditioning: the homeless, as well as residents of low-income neighborhoods and mobile homes. Workers who work outdoors, people with pre-existing health conditions and the elderly are also at higher risk.
Last year in Maricopa County, homeless people accounted for 49% of heat-related deaths and 57% due to substance use such as drugs or alcohol. Therefore, efforts to save people from dying in extreme temperatures must focus on these vulnerable populations.
Maricopa County tried to do this in 2023 by expanding its network of cooling centers and hydration stations, but then record 31 consecutive days with a temperature of 110 degrees or higher. The number of deaths from the heat has risen sharply.
