Long-time residents of southern Arizona said they’d never seen anything like this. A wall of dust and winds gusting over 60mph swept from near Tucson to the Phoenix area Tuesday afternoon. National Weather Service radar measured the height of the wall of dust up to 10,000 feet tall. Other reports indicated the storm was 50 miles wide in some spots. 8,000 residents lost power and flights were grounded for an hour.
It looks like this storm may have developed from a thunderstorm downdraft. As air rushes out of a thunderstorm in arid regions, it can pick up a lot of dust. Another term for this phenomena is “haboob.” The Phoenix area sees about 3 of these storms per year on average between June and September. At this time of the year, spotty thunderstorms develop due to the monsoon season.