Haboob Part II

I'm not sure when this was, but this gif was created by the National Weather Service in Lubbock, TX, from an event they obviously had in their county warning area. It explains how a haboob can form very well. In AZ, the monsoon season kicks in. You get thunderstorms around, cool rain falls..producing cool/dense outflow. The air spreads out, and if the downdraft is strong enough, results in rather high winds. Those high winds pick up sand/dust and create the haboob event (a strong sandstorm.)

edit: found the event on the Lubbock, TX NWS page:
http://www.srh.noaa.gov/lub/?n=events-2006-20060622_haboob

Click for a larger image