The buzzing begins on restaurant tables and in gym lockers, usually in the late afternoon, when temperatures roar up to 110 degrees. Electronic devices rattle pockets and purses with an automated, chiding warning from the National Weather Service.
"Dust Storm Warning," it reads. "Avoid travel."
Longtime desert residents irritably silence their phones. Tourists smile and sweat a little and keep an eye on the windows.
Sometimes what they see is spectacular, from a distance — much of Arizona is best enjoyed from a distance: a wave of yellows and oranges and reds rolling in before faraway fountains of rain.