"Dry fog" in Praia, Cape Verde

View looking east from the top of Hotel Perola in Praia (Santiago island, Cape Verde) on the afternoon of January 23, 2018. This photo was taken on a dry day with low humidity. The apparent fog is from a Saharan dust storm: on a clear day, visibility is significantly better. The low-visibility conditions grounded flights throughout the Cape Verde archipelago for two days. Saharan dust storms are important not only for aviation, but also because they deliver minerals (and nutrients) to faraway regions. The influx of Saharan dust-derived nutrients is thought to maintain ecosystem productivity in the distant Amazon basin, a critically important harbor for biodiversity and a significant carbon sink. Photo credit: Mark Edwards.