An Overview of the SNOWIE Field Campaign

The Seeded and Natural Orographic Wintertime clouds: the Idaho Experiment (SNOWIE) field campaign was conducted between January–March 2017 based in Boise, Idaho. The overarching objective of SNOWIE is to gain a better understanding of factors that impact natural ice production and to determine under what conditions cloud seeding with silver iodide might influence the production of ice and precipitation in orographic winter clouds. The experimental design of SNOWIE included a comprehensive suite of ground-based, remote sensing, and airborne instruments focused on measuring the precipitation process in seeded and natural orographic clouds. Given an active and wetter than normal winter during SNOWIE, the project was able to collect measurements in 24 Intensive Observing Periods (IOPs) during the 10-week campaign. The IOPs occurred in orographic clouds that exhibited a wide variety of characteristics, resulting in a rich data set that was collected. In fact, measurements from SNOWIE provide direct, incontrovertible evidence of the effects of cloud seeding from the initiation of first ice through growth of crystals by deposition and riming to the eventual fallout of precipitation. These data will be used to validate and constrain numerical models that explicitly simulate the physical effects of cloud seeding, thereby allowing numerical verification of seeding effectiveness. This presentation will describe the experimental design of the project, and provide an overview of SNOWIE IOPs and a few highlights from the campaign.