At least 18 people have died from heat in the Phoenix area this year and another 69 deaths are under investigation, according to a weekly heat report released Wednesday by the Maricopa County Department of Public Health.
The deaths, which have been recorded through July 15, illustrate the serious risk of heat even in places like Phoenix, where residents are familiar with extreme temperatures and where public health officials are highly focused on the issue. Data from previous years shows that heat deaths are intertwined with the opioid and housing crises in the Phoenix area.
“We truly believe that all of these heat-related deaths are preventable,” said Dr. Nick Staab, a medical epidemiologist with the Maricopa County Department of Public Health. «We’re seeing increasing numbers and obviously that’s why we want to bring attention to this to make sure everyone has a plan.»
Phoenix set a record for consecutive days of 110 degrees Fahrenheit heat on Tuesday. The overnight temperature did not dip below 97 F, a new record, according to the National Weather Service.
Forecasts suggest oppressive heat will persist for at least another week in the Southwest. More than 80 million US residents are expected to experience a heat index above 105 F this week, according to the agency. More record heat is expected in the states of Four Corners, Texas, the lower Mississippi Valley and southern Florida by the end of the week.
In the Phoenix area, the percentage of heat-related hospital visits has risen sharply in recent weeks, according to Wednesday’s report. Six more deaths were confirmed this week. Of the 18 confirmed heat deaths since April, four have occurred indoors and involved cases with air conditioning «not working» or units not turned on.
The death data provides an early and incomplete view of the toll of the heat wave on human health in the Phoenix area. Heat death data can take weeks or months to report and investigate.
“It may not give an accurate picture of what is happening during this heat wave,” Staab said. “It takes time to complete those investigations and ensure that all of those deaths are accounted for.”
Last year, heat contributed to 425 deaths in Maricopa County, about 25% more than the previous year, according to a report released in June. In cases where such data was known, about 56% of heat deaths involved homeless people. Two-thirds of the deaths involved the use of drugs or alcohol.
“It can be a perfect storm,” Staab said, when issues like heat, homelessness and opioid abuse collide.
The Phoenix area has made investments in heat mitigation. In the fall of 2021, the city of Phoenix hired an Arizona State University associate professor, Dave Hondula, to lead one of the first city heat response offices in the country. The Maricopa Association of Governments coordinates one of the most sophisticated networks of cooling sites in the nation. The county health department has revamped its reporting to ensure heat deaths are accounted for and is one of the few to publish weekly reports on heat deaths.
So far, heat deaths are on track to be lower this year, even as this intense heat event continues. Staab said a relatively cool June could have played a role in that statistic, but it doesn’t take extreme temperatures to kill.
“Historically, we noticed that our heat-related deaths are not necessarily seen on days that have heat advisories. It’s not necessarily the hottest day that puts you at risk. It’s hot all season long,” he said, adding that the season runs from April to October in the Phoenix area. «For our highest-risk people, the difference between 105 and 115 may not be that significant.»
So far, utilities in Arizona’s largest cities seem to be working. Officials in Tempe and Phoenix said municipal water use did not exceed typical summer highs.
“This is what our system is designed to do,” said Max Wilson, deputy director of Phoenix Water Services.
Eric Iwersen, director of sustainability and resiliency for the city of Tempe, said local electricity use rose to record levels as people turned their air conditioning units on full blast.
The Salt River Project, an energy provider in the Phoenix and Tempe areas, experienced a new multi-day record of electricity demand on July 14 and 15, according to Erica Roelfs, a company spokeswoman.
“So far in July, peak system demand is almost 5% higher than last year’s peak,” he said in an email, adding that there were no unplanned service outages for customers this month.
CORRECTION (July 19, 2023, 3:51 pm ET): An earlier version of this article misspelled the last name of the City of Tempe’s director of sustainability and resiliency. He is Eric Iwersen, not Eric Iverson.