Covering the essentials of weather modification, this manual of professional practice guides the manager through the professional practice for operational cloud seeding, from materials and devices necessary to produce ice crystal-forming nuclei to the methods for distributing the artificially produced nuclei through cloud masses.

This manual of professional practice, "Guidelines for Cloud Seeding to Augment Precipitation" (ASCE Manual No. 81), is the outgrowth of a committee report by the same title published by the ASCE Weather Modification Committee in the March 1983 issue of "Journal of Irrigation and Drainage Engineering". A task committee of the ASCE Climate and Weather Change Committee has expanded and updated this report to provide water resources managers and others who might become involved in the decision-making process for implementing a cloud seeding project with the necessary guidelines. The sections of this manual cover essentials of weather modification, including the social, legal, environmental, and economic aspects as well as the scientific basis. Further, the manager is guided through the professional practice for operational cloud seeding, from materials and devices necessary to produce ice crystal-forming nuclei to the methods for distributing the artificially produced nuclei through cloud masses. In addition, methods of instrumentation that are used to provide input to real-time decisions and evaluate results are discussed. Finally, this manual outlines the steps that must be taken to implement a cloud seeding project. A glossary of terms is appended.