I was in Phoenix today for meetings and to give talks on geologic hazards to the annual meeting of the Arizona Emergency Services Association, which put me on the road home to Tucson late this afternoon when monsoon storms and winds were gearing up.
Just south of Phoenix, there were too many dust devils to count. At Casa Grande, the midway point on the drive, parts of town were disappearing under dust clouds, that also engulfed sections of I-10, limiting visibility to about 1/4 mile. Another dust storm, smaller, but less visibility, south of town, and the last of three as I neared Picacho Peak.
On top of that the temperature in Phoenix was 114. Tucson felt balmy at 97. And I can't even say it was a dry heat, because of the monsoon humidity. Here's another video of recent Phoenix-area dust storms (not one that I drove through today however).
Stephanoceras humphriesianum Ammonite Fossil
14 hours ago