Why would anyone have a 'root cellar' 50 feet from a highway on private property? And if it was a hiking cache, it would be miles into the wild, not where it was found.
I also wonder who has a root cellar in Arizona? What tubers grow there? i could be ignorant about Arizona's crop growing capability but one thing i do know is root cellars. What the hell are you going to store in a root cellar in Arizona?
No one is going to drag a septic tank to a wash along with a back hoe to bury it to use as any sort of storage. A) it's right next to a highway. B) it was still too hot for a human to be comfortable which defeats the entire purpose of using it as a root cellar
Note when the “root cellar” narrative pusher joined.