Video of the dust storm which enveloped Phoenix, Arizona late Tuesday has gone viral. What caused the massive onslaught of sand?

The sandstorm, also known as a haboob, was produced by the downdrafts of a collapsing thunderstorm complex generated by the Southwest monsoon. These are the same kind of downdrafts which produced damaging thunderstorm winds in Washington, D.C. on Sunday. When the downdrafts - made up of rapidly descending air - smashed down on the desert ground, they stirred up large amounts of sand and dust, subsequently carried forth by the storm outflow.

Haboobs are fairly common in the Southwest and other desert climates. But yesterday’s version was unusually intense. Mike Oblinski, who shot the time lapse video above wrote: “No words to describe this. I’ve lived in Phoenix for 35 years and seen tons of dust storms. This was something else entirely.” Wunderground’s Jeff Masters offers an explanation for the storm’s ferocity:

The amount of dust was much greater than is usual for one of these storms, due to the large size of the thunderstorm complex, and the extreme drought conditions the region has been experiencing. As the haboob hit Phoenix, winds gusted to 53 mph at Sky Harbor International Airport, and the airport was forced to shut down for 45 minutes due to visibilities that fell as low as 1/8 mile. The airport received only 0.04” of rain from the storm, but large regions of Southern Arizona got 1 - 2 inches of rain overnight due to the monsoon thunderstorms.


Worth watching: a dramatic video from Scott Wood photography

For more photos and multimedia, see BlogPost and this photo gallery.