If you live in a climate like mine, where the highs can crest 120 degrees in the shade, you live in fear of the electricity going out, and particularly of a massive power failure.
I’ve lived without heat in sub-freezing temps. It’s not only possible, it’s not that awful for a twelve-hour stretch. You just pile on the blankets, double up on socks, do everything you must with thin gloves on, drink hot liquid if you have a gas stove or way to heat it, and you can survive it. Your own body provides the heat you need, and the only trick is to trap it and not let it drift away from you.
But 120 degrees in the shade is 140+ in the sun, and if your house is in the sun (a pretty sure bet in the desert!), and the electricity fails, in twelve hours, you could be dead: Dead of heat stroke, dead of a stroke or heart attack, and miserable before you go to meet your maker.
If you remembered to put gas in your car (another reason to never let it fall under 50% full), perhaps you can drive out of the outage area and to a place you can find a cool building. Perhaps you have a generator and sufficient gasoline to run it for days and days--but I bet you don’t. Without electricity over a wide area, gas stations can't pump gas.
Sometimes a power outage stretches for hundreds of miles, and driving away from it is impossible. Or it happens when your car is in the shop, and you’re stuck at home in the heat.
So here’s something you can do to cool yourself down 10 to 20 degrees, which could be the difference between life and death. Keep block ice frozen all the time in warm weather if you have a big freezer--or keep water in plastic zipper bags frozen in a normal-size freezer, and put that ice in a cheap Styrofoam cooler, and run a fan past it. A DC fan can be run off a tiny solar panel hung out the window, and if you check at Amazon, you’ll see they have solar fans that are exact this--a panel, cable, and fan. So you get the fan going, you blow it over the ice, and you and your family stay in a smallish room and sit still, and you’ll be cooler than you were.
You can even pre-make a pretty nifty device like this: Either use a solar fan with the remote panel you can hang out the window to keep it running, or buy a $150 rechargeable lithium battery that you can plug the fan into.
Don’t move around as you enjoy your homemade cooling system. Wear light clothing. Read a book, play a card game, or nap. Drink a lot of water. Bathe your face occasionally with a damp cloth. Stay cool until the sun goes down. And survive.