How Arizona is preparing for health dangers of severe heat-related events caused by climate change


Hannah Saunders


After warming approximately two degrees Fahrenheit within the last century, Arizona is expected to see a continued increase in extreme weather events, including heat, fires, and floods. Extremely hot days can not only be unhealthy, but they can also be deadly. The state of Arizona continues to address these dangers through education and emergency plans. 

A recently released ACS Publications study titled “How Blackouts during Heat Waves Amplify Mortality and Morbidity Risk” highlights the dangers of extreme heat events in Phoenix paired with electrical grid failures. The study meshed simulated heat exposure data during historical heat waves in Phoenix, Atlanta, and Detroit with heat-related morbidity changes in response to electrical grid failure events. 


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“We find the concurrence of a multi-day blackout event with heat wave conditions to more than double the estimated rate of heat-related mortality across all three cities, and to require medical attention for between 3% (Atlanta) and more than 50% (Phoenix) of the total urban population in present and future time periods,” stated the study. 

Symptoms of heat exhaustion include dizziness, thirst, headaches, heavy sweating, nausea, and weakness. Those experiencing symptoms should move to a cooler area, loosen their clothes, sip cold water, and seek medical attention if symptoms don’t improve because heat exhaustion can turn into heat stroke. 

Symptoms of a heat stroke include confusion, dizziness, and becoming unconscious, and individuals should call 911 immediately, while cooling with water and ice, moving the person to a cooler area, and loosening clothing. For protection, individuals are encouraged to limit outdoor activities during hot days, wear light-fitting and light-colored clothing, and drink plenty of water. 


Image: ADHS


Will Humble, executive director of the Arizona Public Health Association, has 35 years of experience in the public health sector, including over 20 years at the Arizona Department of Health Services (ADHS) where he served as Agency Director from 2009 to 2015. He spoke with State of Reform about power outages and heat-related illness through his perspective as a former state government employee.

He said power outages tended to be related to weather conditions, including thunderstorm microbursts, or lightning strikes at transformers or substations, and were generally localized to neighborhoods, or areas containing 10-20,000 individuals.

“Our biggest concern was always special needs populations, and working with the county health departments and emergency management so they knew where people were that were dependent on electricity for survival, like people who need electricity for their medical devices,” Humble said. 

During his time working for the state, Humble was proactive about educating the public on heat-related illness: he spread messages to the media about the risks of leaving children unattended in cars, and worked with several cities on plans to assist the unhoused population during extreme heat events.

“The [most important thing] is to have a plan,” Humble said.

Climate Check, a company that highlights climate-related risks through assessments and reports, ranked Arizona in 13th place out of all states for high heat risk. Climate Check estimates that in 2050, the average number of extremely hot days Arizonans will experience will be about 43. Extreme heat considerations vary from each area, with 113 degrees Fahrenheit described as extremely hot for Lake Havasu City, and 89 degrees Fahrenheit considered as extreme heat for Flagstaff. 

An ADHS tracker shows that heat-caused and heat-related deaths have increased in Arizona over the past decade. In 2011, there were 123 recorded heat-caused deaths and 177 recorded heat-related deaths, but those rates jumped in 2020 to 313 and 522, respectively. By 2021, ADHS reported 302 heat-caused deaths and 522 heat-related deaths. 

The department also tracks heat-related emergency department visits and inpatient hospital admissions. In 2021, there were 2,873 reported emergency department visits for heat-related illness, of which, 1,813 or 63.1%, were heat caused—meaning that the primary diagnosis was listed as exposure to excessive natural heat. That year, there were 920 recorded heat-related inpatient hospitalizations, of which 412, or 44.8% were heat caused.

ADHS’s Preparedness Office is in charge of the All Hazard Emergency Preparedness Plan, and the Extreme Heat Incident Annex. The emergency preparedness plan was last updated in April, and states that between 2010 and 2020, Arizona heat was responsible for 2,429 deaths. Of those deaths, 1,748 were Arizona residents, while 681 were non-residents. 

“Data shows that extreme weather events, such as heat waves, will continue to become more frequent as well as more severe,” stated the emergency preparedness plan. “Observed warming trends suggest that Arizona will experience significant warming in the coming years which, in turn, could have a significant impact on air quality, public health, and critical infrastructure.” 

During summertime, Arizona experiences numerous days of triple-digit heat that are generally accompanied by warm overnight temperatures. Since heat stroke is fast-setting and has a high mortality rate, early identification and prevention are essential. ADHS works with stakeholders and partners to raise awareness about heat in several ways.

“Each year, ADHS collaborates with partners to highlight the importance of staying safe during the heat season and to spread awareness about the challenges of extreme heat in May,” Tom Herrmann, ADHS public information officer, told State of Reform. “This year, our awareness campaign posts received 34,459 impressions (think of this as views), and over 400 engagements (someone liked, commented, or shared the post).”

ADHS also sends heat alert messages to over 37,000 subscribers, according to Herrmann, who added that during summer months, the department publishes heat-related illness messaging including cooling center locations, facts about extreme heat and health, and tips to prevent heat-related illness. 

“Our stakeholders have brought up the concern of blackouts during the summer season, and we realize it is an important issue to address,” Herrmann said. “In case of a blackout, our emergency response partners at DEMA [Department of Emergency and Military Affairs] would coordinate efforts and we would support in the appropriate capacity.” 

If individuals do not have available air conditioning in their homes during power outages that occur with extreme heat events, Herrmann suggests contacting the local health department or to locate a local air-conditioned shelter. He cited additional CDC recommendations such as taking cool showers or baths; spending time in an air conditioned shopping mall or public library; and not relying solely on fans to remain cool. 

ADHS also published a Heat Response Incident Annex, which defines the roles and actions necessary to provide a coordinated heat-related response in the state. The annex defines how ADHS will use the Public Health Incident Management System to address extreme heat incidents, including the requirement for the Arizona Health Care Cost Containment System to collaborate with unhoused outreach programs to perform wellness checks on the unhoused population. 

Herrmann also said the department works with the Arizona Refugee Resettlement Program and Maricopa County to raise awareness about heat-related illness among the refugee population by providing brochures and translating them into their native language.