Standard Practice for the Design, Operation, and Evaluation of Supercooled Fog Dispersal Projects

Prepared by the Atmospheric Water Management Standards Committee of the Standards Development Council of the Environmental and Water Resources Institute of ASCE. Standard Practice for the Design, Operation, and Evaluation of Supercooled Fog Dispersal Projects, ANSI/ASCE/EWRI 44-20, presents guidelines for programs aimed at dispersing supercooled fog. 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 using state-of-the-art supercooled fog dispersal technologies to increase visibility.

This updated standard describes the process through which supercooled fog dispersal operations should be designed, conducted, and evaluated, and includes new material dealing with recent technological improvements. A review of supercooled fog dispersal technology is followed by an overview of fog characteristics. The design of these projects encompasses such topics as project scope, delivery methods, seeding agent selection, targeting and delivery considerations, and seeding suspension criteria. Aspects of conducting a dispersal project include the operational manual, personnel requirements, decision making, communications, and public information and safety considerations. Methods of evaluating a project are described.

Standard 44-20 is particularly useful to hydrologists, hydrometeorologists, environmental and water resources engineers, airport and mining operations managers, water managers with governmental agencies, surface transportation managers, and others who deal with the limitations posed by supercooled fog.