Study predicts 12,800 deaths if heat wave and power failure struck Phoenix: Here's what you should know

What would happen if Phoenix is hit with a heatwave and a power grid failure at the same time?

That’s the question behind a new study release this week, and the worst case scenario is scary.

Here's what you should know.

Who's behind the new study?

According to a May 23, 2023 article by the New York Times, the study was published in the journal Environmental Science and Technology.

On the journal's website, a number of people were listed as having contributed to the study, including a number of people from Arizona.

Contributors from Arizona include Ashley Broadbent, Matei Georgescu, and David Hondula. All three are listed as being with Arizona State University's School of Geographical Sciences and Urban Planning,

On ASU's website, Broadbent is listed as an Assistant Research Professor, while Georgescu and Hondula are listed as Associate Professors. All three have listed climate science as one of their areas of expertise.

What did the study say?

The study comes as blackouts across the country have doubled over the past eight years, climate change is making heatwaves, hotter and longer, and cities like Phoenix are increasing its heat islands with every new building, roadway, house and driveway.

The study uses a scenario of Phoenix being hit by a heat wave, with high temperatures hovering around 110F, coupled with a power grid blackout that lasts at least two days.

Based on that scenario, the study found that about half the city’s population - nearly 800,000 people - would suffer from heat-related illnesses, overwhelming the city’s 3000 emergency room beds. In addition, and an estimated 12,800 people would die.

"We’re very excited about the piece of the analysis that we were able to tackle, and we hope it increases conversation between local and federal governments, and how we can be prepared for large scale hazards," said Hondula, who is also Phoenix's first Director of Heat, Mitigation and Response.

"We are looking at those extreme events, so it’s really helpful to see what it does, so they can be evaluated for planning," said ASU Climatologist Erinanne Saffell.

What else is in the study?

The study also offered suggestions, like planting more shade trees and adding reflective coating to roadways and rooftops, which could save thousands of lives, blackout or not.

"Installing or planting shade tree, putting weight on your roof to decrease the load in your building, that will help. All those things will help mitigate the heat island and your experience at night," said Saffell.

"Anything we can do to cool the city would produce big health benefits if we were to have any low probability, high impact disaster scenario like the one that’s contemplated here," said Hondula.

What are people saying about the study?

Researchers admit there are several shortcomings with the study, as the model does not factor in an emergency management response, as well as making an assumption that people will be staying put during the heat wave, instead of leaving town.

What are local utility firms saying about the study?

We reached out to officials with both Arizona Public Service (APS) and Salt River Project (SRP), and officials both firms issued statements in response to our requests for comment.


"APS prepares for the summer season and has adequate power supply ready to meet our customers’ energy needs. Our crews maintain and make upgrades to the grid, replacing aging electrical equipment and installing new technology to continue to provide the reliable service customers count on, and we maintain sufficient resources and a diverse energy mix to meet demand."


"Arizona utilities invest in our regional grid to strongly mitigate the risk of a prolonged outage event from happening, and SRP conducts careful planning to ensure our ability to meet forecasted summer peak demand.

SRP has enough capacity from its power generation resources to meet a forecasted peak energy demand of 7,700 megawatts in summer 2023 (for context, summer 2022 peak demand among SRP customers was 7,620 megawatts). In addition, SRP carries more than 1,200 megawatts of operating reserve capacity resources, which can be called upon in circumstances when generation units are unexpectedly unavailable or when there are changes in the load or the output of variable power resources.

In the event of an energy emergency, SRP initiates a number of steps to avoid outages such as dispatching all available power generating resources, purchasing additional energy supplies on the open market, suspending service to interruptible customers, and asking customers to voluntarily reduce their energy use. As a last resort during an energy shortage, SRP would conduct rotating outages in our service area. A rotating outage, sometimes called a "rolling blackout", occurs when energy supply does not meet customer demand. Typical rotating outages would last about 20 to 30 minutes per circuit, however, providers of critical services, such as hospitals and airports, are exempted from rotating outages.

SRP also regularly conducts planning drills with state emergency response agencies, and carries spare equipment in preparation for storm events to expedite power restoration and recovery time."