Since 1996, RAP scientists have been involved in evaluating the potential for rainfall enhancement via hygroscopic seeding. The seeding technique introduces hygroscopic material created by flares into updrafts at cloud base during the developing stage of a storm.
Initial development and testing of the technique was done in South Africa, where a randomized experiment showed significant increases in precipitation, as determined from radar, on a storm-by-storm basis.
RAP scientists, in collaboration with South African and Mexican scientists, attempted to confirm and extend the South African results in the Mexican State of Coahuila through the Program for the Augmentation of Precipitation in Coahuila (PARC).(PDF of Phase II of program)
Data were collected during three summer field campaigns, including a confirmatory randomized seeding experiment conducted during the summers of 1997 and 1998.
Based on early results from PARC, the State of Durango in Mexico also became interested in an evaluation program, and a feasibility study began in 1999 (the Durango Rainfall Induction Program - DRIP).