The most common seeding agent is microscopic sized particles of silver iodide. These silver iodide particles are dispersed either from the ground or aircraft. We also have experience using less common seeding materials for specialized applications. Contact us for further information on precipitation augmentation by visiting our Information Request page. Both types are composed of water droplets.
Warm fog is the more common of the two.
Warm fog is microphysically stable and difficult to modify. Cold fog, on the other hand, is microphysically unstable and can be modified much more readily. Ground dispensers can be used to dispense silver iodide or to vent liquefied propane. Aircraft are used to drop small particles of dry ice into the fog. The typical application of this technology is to improve the visibility in the landing zones of airports to prevent aircraft diversions.