A Non-silver Iodide Cloud Seeding Nucleus-Al2O3


  • William G. Finnegan Division of Atmospheric Sciences, Desert Research Institute
  • Lee Ates Concho Cartridge Company Inc.




     Dr. William G. Finnegan, a chemist, devoted most of his research career to advancing our understanding of ice nucleation mechanisms and searching for new ice nucleus formulas as an aid to weather modification operations (especially directed toward enhancement of precipitation from cloud systems). This paper describes his final piece of research related to the development of a non-silver ice nucleus for weather modification applications in order to lighten the financial burden of weather modification programs impacted by the escalating price of silver. Mr. Lee Ates of Concho Cartridge in San Angelo, TX helped Bill on running the necessary experiments of this research project. Bill surely appreciated Lee’s help. Bill said to me several times that without Lee nothing could be accomplished.

     Bill and Lee started this research in early 2008. Bill would come up with a formula and Lee would run it in the cold box at Concho Cartridge. Since the acidity and the solubility of the ice nucleus is important in ice nucleation, Bill would calculate and recalculate the compositions of each chemical in a formula in order to have the right acidity and solubility. He once said “I was working on my new, hopefully effective, solution combustion mixture for ice nuclei generation. It’s interesting chemistry, but whether or not it works is an unknown quantity. I’m working on that supposition that one should do something, even if it’s wrong.” The lack of a cloud chamber sometimes discouraged him. He said “I really wish the CSU cloud chamber was functioning.” Not to be discouraged, he would then think and speculate that a cold box could establish various threshold temperatures and some idea concerning the density of ice crystal formation at cold temperatures could be ascertained. That’s good enough for the new formula development. It still needed in-cloud testing to determine utility. When the news that there were plenty of ice crystals formed in an experiment executed by Lee, Bill would break out in a smile and said “Chemistry is really fun, when you get it to work.” However, when an experiment failed, he would say “This is the way research goes. I will give Lee some new instructions and maybe we’ll succeed next time.” From these interactions we could see Bill’s joy in working with chemistry. He thought about chemistry to his last day on earth. He was a genuine scientist and I deem it a privilege to know Bill and to discuss chemistry with him.




Technical Notes and Correspondence

How to Cite

A Non-silver Iodide Cloud Seeding Nucleus-Al2O3. (2012). The Journal of Weather Modification, 44(1), 101-103. https://doi.org/10.54782/jwm.v44i1.89