Wintertime Glaciogenic Orographic Cloud Seeding—A Review

Since the discovery of cloud seeding effects by Schaefer and Vonnegut in the late 1940s, seeding of wintertime mountain cloud systems has been pursued as a technology to increase water supplies. In this talk I review research conducted over the last 7 decades to understand the efficacy of wintertime orographic cloud seeding, and the impact of seeding on increasing water supplies of a target mountain basin. The review first considers work done during the 20th century when observational technologies and numerical models were not as advanced and studies were more constrained by the limitations of the technology of the time. The second part of the review considers recent experiments and modeling efforts that take advantage of current technologies to assess whether silver iodide seeding from ground generators and/or aircraft impacts the amount and distribution of snow falling across a mountain watershed. The review ends with a look to the future of cloud seeding research, focusing on key remaining uncertainties for enhancement of snowfall from orographic cloud systems.