Cloud Seeding in California [2023 DWR Report]

Precipitation enhancement, commonly called “cloud seeding” or “weather modification” is a scientific method to artificially stimulate clouds to produce more rainfall and snowfall than would be produced naturally. The primary mechanism is to inject substances, such as silver iodide or ice crystals (cloud seeding agents), into the clouds, enabling snowflakes and raindrops to form more easily. Various cloud seeding programs have been operational since the late 1950s. The majority of programs continue for a number of years during winter months and as conditions warrant. The following is a summary on previous cloud seeding programs in California.