Physical aspects of weather modification

Successful weather modification (cloud seeding or rain making) is brought about by either of two processes. (1) by coagulation of moisture droplets in the cloud by use of pulverized dry ice, or (2) by use of silver iodide smoke particles that have the property of nucleating ice particles in the clouds. There must be abundant moisture or moisture laden clouds in order to produce artificial rain or to trigger the process of rainfall. Research dealing with the physical properties of the most likely cloud formations and atmospheric conditions for successful weather modification has been carried on in the past, is still continuing, and must be extended into the future.