Dust storm near Laguna Mar Chiquita, Argentina
Mar Chiquita is a huge permanent lagoon of salt water, located in the Argentine provinces of Cordoba and Santiago del Estero. It is about 100 km long and 40 km wide, and up to 4 m deep. The lake level shows great variations by year, with its surface area and salinity changing a great deal. Starting in 1977, and due to unusually wet and rainy years, the level of the lagoon has increased abnormally and salt concentration decreased accordingly.
In this MODIS Aqua image from July 27, 2006, there is a dust storm in the Laguna Mar Chiquita region. You can see the dust as gray 'plumes'. The red dots represent active fires in the region.