North American Weather Consultants, Inc.
The World's Longest Standing Private Weather Modification Company

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Publications Related to Weather Modification

Position Statement on the NRC Report - "Critical Issues
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Can cloud seeding be effectively conducted in your area?  Find out!

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A few of our weather modification services are listed below. If you don't see the service you desire, please contact us by phone or email and we can discuss your needs in further detail.

Snowfall and Rainfall Augmentation

North American Weather Consultants has conducted more than 200 weather modification projects involving snowfall or rainfall augmentation world-wide since 1950. These programs have been designed to increase the naturally occurring rainfall or snowfall in a selected target area by utilizing cloud seeding agents to increase the efficiency of the natural precipitation process. 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. Typical precipitation increases from the programs range from 10 to 15 percent (in wintertime cold climate areas) to 20 to 25 percent (in more maritime tropical regions) over what would have occurred naturally. Users of this technology range from irrigation districts, municipalities, hydroelectric facilities and recreational areas (ski areas). A brief summary of the scientific basis for cloud seeding is available here. Please contact us for further information.

Fog Seeding/Fog Dissipation

There are two primary fog types: warm and cold fog. These fog types are differentiated by temperature, with warm fog occurring at 32°F (0°C)or above, and cold fog at temperatures below 32°F (0°C). Both types are composed of water droplets. Warm fog is the more common of the two in most parts of the world, is microphysically stable and difficult to modify. Cold fog, on the other hand, is microphysically unstable and can be modified much more readily via fog seeding. Water droplets in these fogs can be frozen by the introduction of a heterogeneous seeding agent such as silver iodide or homogeneous agents such as dry ice (solid carbon dioxide) or liquefied propane. These seeding techniques are commonly known as "fog clearing" or "fog dispersal". Ground-based equipment can be used to dispense silver iodide or to vent liquefied propane. Aircraft can be used to drop small particles of dry ice into the fog. The typical application of this technology is to improve the visibility in the vicinity of airports.

Another method for the reduction of supercooled fog involves the introduction of liquid carbon dioxide into the fog from the ground. The liquid carbon dioxide can be dispersed into the fog by moving vehicles, in a quantity sufficient to diminish the supercooled fog. The method is of potential value in activities in which poor visibility due to the presence of supercooled fog is a constraining factor (e.g. winter airport operations). Please contact us for further information.

Feasibility/Design/Evaluation Studies

North American Weather Consultants not only conducts operational cloud seeding programs, but has also been intimately involved in numerous research oriented cloud seeding programs since the mid-1950's. This combined operational and research experience allows us to assess the feasibility of conducting a cloud seeding program for snowfall or rainfall augmentation in a given area, design an effective program and evaluation method if a program appears to be feasible, and evaluate the effectiveness of cloud seeding programs. Please contact us for more information.

Airborne Cloud Physics and Tracer Studies

Observations above the surface of the earth are frequently of interest to a variety of users. In weather studies and weather modification research, North American Weather Consultants has utilized aircraft to obtain measurements within clouds, including temperature, dew point, water content, ice particle concentration, and wind direction and speed. Further, an atmospheric tracer, for example sulfur hexafluoride, can be released from either a ground or airborne location, then tracked by an aircraft equipped with a special real-time analyzer that can detect minute concentrations of sulfur hexafluoride downwind for tens of kilometers from the source.

These airborne observations can be utilized to assess the seeding potential of different cloud forms affecting a given area. Use of an atmospheric tracer released upwind of these cloud forms can be used to assess the effectiveness of different seeding locations. Airborne tracer measurements have also been conducted to address air quality and pollutant dispersion issues, in an ambient air context as well as in tracking point/facility source plumes. Please contact us for more information.

Technology Transfer/Seeding Equipment

Cloud seeding programs can be designed to address specific meteorological conditions and client needs. Qualified client personnel can work with our personnel learning cloud seeding techniques. Given adequate cross-training of personnel, the client personnel can gain the necessary skills that will eventually allow them to assume the on-going responsibility of conducting a successful cloud seeding program.

In the years of involvement in conducting cloud seeding programs, we have developed and installed a variety of specialized equipment and computer software. Examples include manual or remotely controlled ground-based silver iodide generators and airborne silver iodide pyrotechnic dispensers. Equipment can be designed and fabricated for clients who desire to acquire equipment to conduct programs either operated by their personnel or under contract with North American Weather Consultants. Please contact us for more information about these programs.


Publications Related to Weather Modification


Map of NAWC Operational Cloud Seeding Projects in the Western United States (1950 - 2014)


Additional information on cloud seeding and weather modification can be found at the following websites:

Utah Division of Water Resources - Cloud Seeding Programs

Weather Modification Association

Desert Research Institute Cloud Seeding Page

Additional publications on cloud seeding are available from the Weather Modification Association on this page:

North American Weather Consultants, Inc.

8180 South Highland Dr., Suite B-2
Sandy, Utah 84093

Telephone:   801-942-9005

Facsimile:   801-942-9007


Contacts:  Garrett Cammans, President

Copyright 2021, North American Weather Consultants Inc., Sandy, Utah, USA.

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