From the Arabic for “violent storm”, a haboob is exactly that: a thunderstorm-powered rolling wave of dust and sand. The blast of downward air pushed along in front of a thunderstorm causes a convective downburst, forcing cool air towards the ground, where it streams outward and, in dry regions, stirs up dust and sand into a haboob.
Haboobs are becoming more likely in the United States as an ongoing drought afflicts the south-western states. Scientists in Arizona have recorded downward blasts that spawned walls of dust up to 3 000 metres high. –Alex Hutchinson