Colorado has approved the application of the National Center for Atmospheric Research for a permit to conduct the 1973 field research program of the National Hail Research Experiment in northeastern Colorado this spring and summer. According to William Swinbank, director of the hail experiment, NHRE has two goals: to learn more about the physics and dynamics of hailstorms and to test the feasibility of using cloud seeding to reduce damaging hail. Swinbank emphasizes that the program is a scientific experiment, not a large-scale weather modification program.
The experiment is designed to study hailstorms over a five-year period in an area along the Colorado-Nebraska border northwest of Sterling and southeast of Kimball, Nebraska. More than 200 ground stations have been set up to measure hailfall, rainfall, and other weather features in this area, which is roughly in the shape of a square 25 miles on each side. Two meteorological radar systems, one at the NHRE field headquarters near Grover, Colorado, and the other just north of Fort Morgan, are used to track and probe hailstorms. Research aircraft, weather balloons, and other tools of atmospheric research are used to gather additional data.