Cloud Seeding Forms Measurable Snowfall
Cloud Seeding Forms Measurable Snowfall
Snowpack in the mountains is the main source of freshwater for the western U.S. Given the rapid population increase and changing patterns of snowfall, the western U.S. faces challenges when responding to water scarcity and managing existing water resources.
One man-made solution for these challenges is to produce more snowfall in the mountains using cloud seeding. Cloud seeding works by distributing particles that form ice into the clouds. When clouds that possess the right characteristics form over the mountains in the winter, inserting cloud-seeding particles at the right time and place can improve ice and snow formation leading to extra snowfall. However, the entire physical chain-of-events of cloud seeding hoping to yield additional snow had not been scientifically proven until the Seeded and Natural Orographic Wintertime clouds - the Idaho Experiment (SNOWIE) field campaign took place in Idaho during the early 2017. The detailed observations from weather radars and instruments flown on research aircraft in SNOWIE not only clearly showed the cloud-seeding signals, but also collected quantitative estimates of the extra water reaching the ground that was directly related to the cloud seeding.
The SNOWIE experiment changed the narrative around cloud seeding from “Does it work?” to “When and how does it work most effectively?” As a result of SNOWIE, nearly every western U.S. state, as well as many countries around the world, have begun or (re)invigorated efforts to consider cloud seeding as a possible water-resource management strategy. In addition, SNOWIE set the example for identifying patterns from airborne cloud seeding with radar, and several operational cloud-seeding programs have now observed this signature. The SNOWIE high-quality scientific datasets have also improved our fundamental understanding of natural and seeded cloud processes, which are critical for improving numerical models capable of simulating natural and seeded clouds, such as the WRF-WxMod® system. These numerical models are useful tools to quantify seeding effects over watersheds and seasons.