NEWS STORIES - Updated 3/7/17
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The Weather Modification Association publishes the Journal of Weather Modification

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Finally, members have provided for our repository publications they feel pertinent to the subject of Weather Modification. View Publications Repository.

  Other Documents are available:  

The Weather Modification Association's Response to The National Research Council's Report Titled, "CRITICAL ISSUES IN WEATHER MODIFICATION RESEARCH" has been completed.

To read the March 18, 2004 Press Release, the Response's Executive Summary, or to download the entire WMA response, click here.  The WMA Review Panel was comprised of: Dr. Harold D. Orville (Chair), Bruce A. Boe, George W. Bomar, Dr. William R. Cotton, Byron L. Marler, and Dr. Joseph A. Warburton.  


Standard Practice for the Design and Operation of Hail Suppression Programs, Standard ASCE/EWRI 39-03, is now available (click here to purchase from the ASCE online bookstore).  It provides useful information for implementing operational hail suppression activities, including the successful design, conduct, and evaluation of such efforts. Because the effects for seeding clouds for hail suppression on a storm’s rainfall are not fully understood, several hail suppression concepts have been formulated. The five concepts most commonly employed in the context of operational hail suppression projects are included in this book: beneficial competition, early rainout, trajectory lowering, promotion of coalescence, and dynamic effects. The Standard uses the best scientific and technical knowledge currently available on hail suppression to ascribe a process through which hail suppression should be designed, organized, and conducted to optimize the likelihood of success


Standard Practice for the Design and Operation of Precipitation Enhancement Projects, Standard ASCE/EWRI 42-04 is available (click here to purchase from the ASCE online bookstore). It provides state-of-the-art cloud seeding technology applications for precipitation enhancement projects. By utilizing a variety of meteorological and hydrological observations, water resources engineers can evaluate the effectiveness of improving precipitation methods. This Standard covers the history and status of cloud seeding and the concepts, designs, operations, and evaluation of these projects. Natural cloud processes, with an emphasis on artificial intervention through cloud seeding, are discussed. These processes can potentially increase the chances of precipitation reaching the ground. Operational requirements and procedures such as personnel, decision-making, communications, safety issues and seeding suspension criteria are included. Topics include: definition of project scope; targeting and delivery methods; seeding agent selection and equipment considerations; data collection and instrumentation; legal issues and environmental concerns; and evaluation of effects of cloud seeding.


Guidelines for Cloud Seeding to Augment Precipitation, Second Edition (ASCE Manuals and Reports on Engineering Practice No. 81) is now available (click here to purchase from the ASCE online bookstore). This 2006 edition updates the previous 1983 and 1995 versions and provides practical details for using the cloud seeding technology. This newly revised manual incorporates pertinent background on the science and practice of weather modification by cloud seeding to augment precipitation. Topics include the societal, environmental, and economic aspects of precipitation enhancement by cloud seeding; legal aspects associated with weather modification operations; scientific basis; cloud seeding modes; and instrumentation and status of precipitation enhancement technology. The volume also includes an executive summary addressing the complex issues that arise with the development and application of the cloud seeding technology. This manual will provide water resources managers with the resources to make decisions regarding the use of cloud seeding to increase available water supplies.


Standard Practice for the Design and Operation of Supercooled Fog Dispersal Projects, Standard ASCE/EWRI 44-05, is available (click here to purchase from the ASCE online bookstore). It presents the standard practice for conducting supercooled fog dispersal operational programs. Extended periods of fog can have large economic impacts on aviation, tourism, transportation, and mining industries, as well as a negative effect on agriculture. These problems can be reduced through the use of state-of-the-art supercooled fog dispersal technologies. This document describes the process through which such operations should be designed and conducted. It also provides the reader with information on the planning, conduct, and evaluation of such efforts. Topics include: history and status of supercooled fog dispersal technology; fog characteristics; project design and seeding agent delivery methods; operations manual; and evaluation of projects.

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