The National Hail Research Experiment (NHRE), based at NCAR and conducted in northeast Colorado from 1972 to 1976 was one of the largest weather modification experiments up to that time. NHRE used silver iodide seeding techniques to try to reduce the size of hailstones falling from summer storms. Although the experiment failed to confirm any reliable effect from the silver iodide seeding, it was highly successful in giving insight into processes taking place in hailstorms. Here NHRE participants crane their necks to watch a radiosonde ascending over far northeast Colorado near the town of Grover
