Tuesday, August 23, 2016

What Is a Haboob?

Dan Pope of ABC 4 Utah shared a remarkable photo yesterday of a Haboob near Phoenix, Arizona.  The credit is ambiguous, so I share the full facebook post below to provide as much credit as possible.

A Haboob is a dust storm generated typically in arid regions by the outflow from a thunderstorm, convective cloud, or precipitation system.  Within these clouds and precipitation systems, cooling by precipitation produces a downdraft or downdrafts, a cold pool at the surface, and strong winds.  The leading edge of the cold pool and strong winds is known as a gust front and, in areas where this leads to dust emissions from the surface, typically demarcates the leading edge of the Haboob.  I've taken considerable artistic license to crudely sketch this out in the photo below.

Haboobs occur in arid regions around the world.  Areas where the land surface has been disturbed, enabling or enhancing the potential for dust emissions, are vulnerable to Haboob development.  Many iconic photos from the Dust Bowl are Haboobs with dust emissions in that area strongly related to poor agricultural practices combined with long-term drought.  Even today in Arizona and much of the American Southwest, land-surface disturbance is an aggravating factor in Haboob frequency and intensity.

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