Scientists say they used new measuring methods to confirm that cloud seeding can produce snowfall under the right conditions. Researchers used radar and other instruments to measure snowfall levels during experiments carried out in 2017 in the American state of Idaho. The experiments involved scientists from several American universities, as well as the U.S. National Center for Atmospheric Research, or NCAR. A study reporting the results was recently published in Proceedings of the National Academy of Sciences. Cloud seeding has been tested in parts of the United States since the 1940s. It involves injecting various substances into clouds to produce precipitation rain, snow or ice that falls to the ground. The process can cause ice to form and build up inside the clouds until it falls.