A haboob is caused by a downdraft of air in a thunderstorm that blows a huge amount of dust as it moves across a desert area. Here is time-lapse video of a haboob in the Phoenix area in 2011.
The Haboob movement is in ABA form. It begins quietly with a diminished fifth in the left hand of the piano that represents foreboding. This low diminished fifth is present throughout the A section, sometimes occurring in the Horn and bassoon as well. A swirling dust motif is introduced first as just three notes and then expanding as the section progresses. Trills also represent swirling dust. The A section builds in intensity leading into the B section that represents the Haboob itself.
The B section is in 2/4 except for one 3/8 measure. It begins with a wall of sound in the form of a diminished 7th chord. In fact, all the material of this section is derived from the diminished 7th chord. There are three elements to the section. The first is the wall of sound that represents the wall of dust. It appears in all instruments at various times and becomes syncopated as the section progresses. The second is the swirling dust motifs that are similar to the first section. Lastly, there is the staccato eighth note ostinato that represents people scurrying to the safety of indoors.
The last section is essentially a reverse of the opening section where it moves from intensity to quietude as the dust storm winds down. The low diminished fifth interval takes on a different meaning than when it occurs in the first section. Here it represents the devastation that was left behind by the haboob.
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