Utah has been cloud seeding since the early 1950s to help augment the state’s water supply. The Cloud Seeding Act of 1973 gave the authority to the Utah Division of Water Resources to oversee state cloud seeding projects. Ground-based seeders shoot silver iodide into winter clouds to stimulate the precipitation process and generate snow. Placed along foothills and higher elevations, the release of the cloud seeds is timed so that air currents carry them high into the cloud.
This process is effective because clouds are formed by water vapor and dust. Under certain natural conditions those water droplets will freeze together around the dust or other particles and, when heavy enough, will fall from the sky as snow. Often, there is more snow that can fall but limited by the number of particles around which ice crystals can form. That is why adding particles, or seeds, facilitates and accelerates the process which may lead to more snow falling than would have under natural conditions.