Precipitation control

TitlePrecipitation control
Publication TypeConference Proceedings
Year of Conference1950
AuthorsBarnes, C. S.
Conference Name18th Annual Western Snow Conference
Series TitleProceedings of the 18th Annual Western Snow Conference
Date PublishedApril 1950
PublisherWestern Snow Conference
Conference LocationBoulder City, Nevada
KeywordsWeather modification research

The Precipitation Control Company of Phoenix, Arizona was formed to develop and perfect the mechanics and techniques of increasing precipitation. Silver iodide from airplane generators is used to seed super-cooled clouds. Calcium chloride is used to cause clouds to thicken and precipitate in non-super-cooled clouds. Ground generators have not proved successful. A technique called 'Advanced Air Mass Seeding' is used on days which appear to be favorable for cloud formation. Small clouds are seeded early in the day, preparing them for precipitation as soon a the clouds cool to the critical temperature. Two or 3 times as much rain is produced due to generation caused by reflected heat form the ground and rising air currents. Over-seeding in cloud structures is often brought about by smokes and vapors with subsequent loss of normal precipitation. The installation of precipitating and cleaning equipment in smoke stacks is recommended to increase the efficiency of seeding by silver iodide.