The Sirocco March 9-12 (1991)
Sirocco most commonly arises from a warm, dry, tropical airmass that is pulled northward by low-pressure cells moving eastward across the Mediterranean Sea, with the wind originating in the Arabian or Sahara deserts. The hotter, drier continental air mixes with the cooler, wetter air of the maritime cyclone, and the counter-clockwise circulation of the low propels the mixed air across the southern coasts of Europe.
Dust in most of the March African dust storms is most cases is a red in color.
The of the path of the Sirocco of March 1991 began in Mauritania and moved eastward to the dune fields of Mali where soil deflated from the surface is yellow. From Mali the storm moved north and crossed the Mediterranean near Tunis and across the Alps where the “yellow snowing” began then to Scandinavia.
The great Sirocco of 1991 Petered out near Arjeplog in northern Sweden where the dust fall in the yellow snow totaled 50,000 tons.
Dust-laden winds, what good are they? Scientists working on soil aerosols of West Africa have traced these aerosols to the Amazon where they contribute to the nutrient budget.