The South Texas Weather Modification Association (STWMA) is a non-profit organization consisting of several water districts committed to enhancing rainfall across the south Texas operation area. Rainfall enhancement is conducted using cloud seeding techniques where aircraft release microscopic particles of silver iodide and calcium chloride into thunderstorms to increase rainfall efficiency.
The association first formed in 1996 and conducted its first cloud seeding mission the following year. After 25 years in existence, the STWMA, based in Pleasanton, continues to perform seeding operations over multiple counties in south-central Texas.
