Aircraft support the hand crews and engines on the Adams Robles Complex fires in southeastern Arizona.
CNN  — 

Residents in parts of Arizona were ordered to evacuate Sunday as firefighters battled several wildfires across the state amid extreme temperatures that have persisted for weeks.

About 160 residents were ordered to evacuate from the Sunflower area in Arizona’s Maricopa County Sunday as a wildfire burned in the Tonto National Forest, authorities said.

Deputies were evacuating residents and advising them to head to the town of Fountain Hills, where an evacuation center was set up, Maricopa County Sheriff’s Office Sgt. Joaquin Enriquez told CNN Sunday evening.

“At this point, the fire is burning in place and crews will monitor and continue some firefighting overnight,” Maricopa County Emergency Management spokesperson Ron Coleman said. “Additional firefighting will continue in the morning.”

Sunflower is about 58 miles northeast of Phoenix, which hit 24 straight days of temperatures at or above 110 degrees, according to a tweet from the National Weather Service. The city saw a high of 114 degrees Sunday.

Over 100 miles away in Yavapai County, where six active wildfires were burning, residents of the community of Cherry were also ordered to flee Sunday.

“The RACETRACK Fire is threatening your area. Please evacuate now,” the Yavapai County Sheriff’s Office said in a “go message” to residents Sunday night.

A special weather statement was in effect for parts of Yavapai County for wind gusts up to 50 mph Sunday, and the National Weather Service had warned residents to “Expect wind shifts for the Grapevine and Race Track fires.”

The fires come amid Arizona’s weeks-long battle with extreme heat, with excessive heat warnings in place across much of central and southern parts of the state Sunday.

There have been at least 18 confirmed heat-related deaths recorded in Maricopa County so far this year as of the second week of July, with another 69 cases under investigation, according to data from the Maricopa County Department of Public Health.

The dangerously hot temperatures are also taxing hospitals in the county as people suffering from heat-related illnesses seek treatment, CNN previously reported.

Maricopa County, where Phoenix is located, is the nation’s fourth largest county in terms of population size, according to the county’s website.

Record-breaking heat across the southern US

The extreme heat across the southern United States has continued to set records through Monday.

Over 55 million people were under heat advisories and excessive heat warnings Sunday across much of the desert Southwest, Intermountain West, South Texas and South Florida, according to the National Weather Service. The heat will slowly spread to the east, meaning it’s likely the number of heat alerts will increase.

Over two dozen records were either set or tied Saturday across cities in Arizona, California, Florida, Idaho, Montana, Nevada, Puerto Rico and Texas.

Miami continues to see consecutive days of a heat index – which takes into account air temperature and humidity and is colloquially known as the “feels like” temperature – exceeding 100, according to the weather service.

On Monday, the city reached a heat index of 110 degrees. An excessive heat warning remains until this evening, with the heat advisory lasting through Tuesday. Heat indices are expected to reach over 100 through at least Wednesday, so the advisories are expected to continue.

El Paso saw a temperature of 104 degrees on Monday, bringing the city to 39 consecutive days with a high temperature above 100 degrees and smashing the previous record of 23.

High temperatures are expected to remain above 100 degrees through the rest of the week. El Paso citizens will remain under a heat advisory until Thursday evening – and that will likely be extended.

Phoenix hit 117 degrees earlier Monday – the 25th consecutive day with a high temperature above 110 degrees. The temperature is expected to remain above 110 degrees through the rest of the week and excessive heat warnings are in effect until Thursday evening.

The Arizona Public Service utility set a record for energy demand during the severe heat wave.

“With more than 1.3 million homes and businesses using electricity to keep cool during Arizona’s record heat wave, APS customers have again made history, setting a new peak for the most energy used. Customer energy use reached 8,193 megawatts (MW) Thursday, July 20. One megawatt powers roughly 160 homes,” the company said in a Monday news release.

“Thursday’s energy use surpassed the all-time peak set just five days earlier on Saturday, July 15. Starting Friday, July 14, APS customers recorded the seven highest peak days ever. The previous peak demand was 7,660 MW set on July 30, 2020.”

The utility serves more than 1.3 million homes and businesses in 11 of Arizona’s 15 counties.

“Despite historic levels of energy usage, APS and its customers experienced no issues related to power supply; and that does not happen by accident. It takes years of planning, maintaining a diverse energy mix, investing in and strengthening the electric system, and most importantly teams of people who are dedicated to keeping the lights on for customers when they need us most,” Ted Geisler, the utility’s president, said in the release. “Arizona summers can be brutal, and APS is here to serve and ready to respond every day whether we’re faced with heat, monsoon storms, wildfires or all of the above.”

CNN Meteorologist Gene Norman and CNN’s Zoe Sottile contributed to this report.