 Studies in the 2000s have given rise to the hypothesis that large amounts of dust reduce the strength of tropical cyclones.In the 1960s and 1970s, the United States government attempted to weaken hurricanes through Project Stormfury by seeding selected storms with silver iodide.It was thought that the seeding would cause supercooled water in the outer rainbands to freeze, causing the inner eyewall to collapse and thus reducing the winds.