On Tuesday, high temperatures in Phoenix topped 110 plus degrees for 19 days in a row, breaking a 49-year-old record.

And as extreme heat continues to stress cities in the South, there are questions about whether their power grids will stand up to the strain.

Research published this year forecasted the mortality risks of a power grid failure during a heat wave in 3 major cities including Phoenix. 

The study found a multi-day power grid blackout during a heat wave would more than double the estimated number of heat related deaths and require medical attention for more than 50% of the total population in Phoenix. 

SEE MORE: Phoenix sets record at 19th straight day of at least 110 degree temps

On July 15, temperatures in Phoenix topped out at 118 degrees. The same day Arizona Public Service, the largest energy company in the state, shattered the demand for energy at 8,200 megawatts.

Back in Texas on July 13th, a major energy company set an unofficial all-time peak of 81,000 megawatts. 

APS says they invest more than 1.5 billion dollars to maintain and upgrade the grid with new technology. 

“We are prepared because we’ve done the maintenance. We’ve done the investment. We’ve done the proactive planning,” said Justin Joiner, Vice President of resource management for APS.

City planning for heatwaves is also drawing federal attention, and hopes of developing a relatively poorly understood aspect of emergency management.

“We’ve had FEMA regional folks at some of our meetings where they’re expressing interest in getting more involved in heat work,” said David Hondula, director of heat response and mitigation for the city of Phoenix.

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