Phoenix heat expert: 800,000 hospitalizations is worst-case scenario

Yes, but: It's also important to recognize that the study evaluated just that: the worst-case scenario, he said.

Zoom in: Hondula said Phoenix's Office of Emergency Management has resources to respond to large-scale hazardous events, including heat wave/blackout combinations.

• He said there are many buildings with backup generators, including hospitals, that are prepared to open to the public during an emergency and transportation plans to shuttle people to these facilities.

Reality check: The likelihood of a multiday power outage across all of Phoenix is low.

• Hondula said researchers at ASU have simulated thousands of disaster scenarios and the worst outcome has been one-sixth of our grid going down at one time.

But, but, but: Small-scale blackouts that impact a handful of neighborhoods at one time are fairly common during summer storms.

• This is why the city's working to increase indoor heat relief stations, he said.

What we're watching: Hondula said the city recently applied for a FEMA grant to ensure all city buildings that serve as cooling centers during the summer have backup generators.

• Phoenix is also applying for a U.S. Forest Service grant that could provide "many millions of dollars" for tree planting.

Of note: The study found that increasing the tree shading to 50% of streets would reduce heat mortality by 27% in Phoenix.