![John Locher FILE - Members of the Henderson Fire Department load Deb Billet, 66, into an ambulance before transporting her to the hospital for heat-related symptoms, Wednesday, July 10, 2024, in Henderson, Nev. Heat is the top cause of weather-related fatalities nationwide. But because investigations of suspected heat deaths can take months, and mishmash of methods counties use to count them, we really don't know exactly how many people died in the most recent heat wave stretching back to July 1. (AP Photo/John Locher, File)](https://mapi.associatedpress.com/v2/items/e1a8177100b54622b5802164393555ef/preview/preview.jpg?s=680x&wm=false)
FILE - Members of the Henderson Fire Department load Deb Billet, 66, into an ambulance before transporting her to the hospital for heat-related symptoms, Wednesday, July 10, 2024, in Henderson, Nev. Heat is the top cause of weather-related fatalities nationwide. But because investigations of suspected heat deaths can take months, and mishmash of methods counties use to count them, we really don't know exactly how many people died in the most recent heat wave stretching back to July 1. (AP Photo/John Locher, File)
![Matt York FILE - Phoenix firefighters give medical attention to a homeless man in the heat, May 30, 2024, in Phoenix. Heat is the top cause of weather-related fatalities nationwide. But because investigations of suspected heat deaths can take months, and mishmash of methods counties use to count them, we really don't know exactly how many people died in the most recent heat wave stretching back to July 1 (AP Photo/Matt York, File)](https://mapi.associatedpress.com/v2/items/9b6d51b7e671478ba35f9916d35e808b/preview/preview.jpg?s=680x&wm=false)
FILE - Phoenix firefighters give medical attention to a homeless man in the heat, May 30, 2024, in Phoenix. Heat is the top cause of weather-related fatalities nationwide. But because investigations of suspected heat deaths can take months, and mishmash of methods counties use to count them, we really don't know exactly how many people died in the most recent heat wave stretching back to July 1 (AP Photo/Matt York, File)
![John Locher FILE - Deb Billet, 66, lies on the ground while Henderson Public Response officers call an ambulance to take her to the hospital for heat-related symptoms Wednesday, July 10, 2024, in Henderson, Nev. Heat is the top cause of weather-related fatalities nationwide. But because investigations of suspected heat deaths can take months, and mishmash of methods counties use to count them, we really don't know exactly how many people died in the most recent heat wave stretching back to July 1. (AP Photo/John Locher, File)](https://mapi.associatedpress.com/v2/items/4143757857a844149d5c567885c93ca7/preview/preview.jpg?s=680x&wm=false)
FILE - Deb Billet, 66, lies on the ground while Henderson Public Response officers call an ambulance to take her to the hospital for heat-related symptoms Wednesday, July 10, 2024, in Henderson, Nev. Heat is the top cause of weather-related fatalities nationwide. But because investigations of suspected heat deaths can take months, and mishmash of methods counties use to count them, we really don't know exactly how many people died in the most recent heat wave stretching back to July 1. (AP Photo/John Locher, File)