Summary

The National Hail Research Experiment (NHRE) was conducted in the tri-state area of Colorado, Nebraska, and Wyoming, with the field headquarters located at Grover, Colorado. This area, during the three years prior to the start of NHRE, had been the site of the Joint Hail Research Project (JHRP), a cooperative study of hailstorms conducted by the Atmospheric Physics Laboratory of the National Oceanic and Atmospheric Administration (NOAA); Colorado State University (CSU); and NCAR. During the period of the JHRP, valuable knowledge was gained concerning local hailstorm statistics and climatology. This information was used in developing the plans for NHRE.

The NHRE field deployments were conducted during the summer months from 1971 through 1976. The first year was devoted to completing the field headquarters complex and evaluating new equipment and operational procedures. The randomized seeding experiment was conducted during the hail seasons from 1972 through 1974 along with a concurrent research program. The objective of the research program was "to gain an increased understanding of all aspects of the cloud dynamics and microphysics governing severe convective storms that produce damaging hailfall at the ground". During 1975, a small-scale field deployment was conducted to test and evaluate new and improved observational systems and to collect research data, if and when, these systems became operational. An extensive field program was conducted during the summer of 1976;  the final field deployment of NHRE. During the field deployments from 1972 through 1976, observations were made on 308 days. From this total, 65 case study days were selected for future research.

Other contributions to the field observation deployments and research efforts were made by the University of Arizona, University of Chicago, Clemson University, University of Colorado, CSU, University of Denver, University of Hawaii, University of Illinois, Illinois State Water Survey (ISWS), Metropolitan State College, University of Nevada, University of Oklahoma, Oregon State University, Panhandle State University, South Dakota School of Mines and Technology (SDSM&T), University of Virginia, University of Wisconsin, and University of Wyoming (UW). Government agencies providing support included: U.S. Air Force, Air Weather Service; U.S. Navy, Naval Electronics Laboratory, Weapons Development Center, Naval Weather Service; U.S. Army, White Sands Proving Grounds; Federal Aviation Administration (FAA); and the Wave Propagation and Atmospheric Physics and Chemistry Laboratories of the NOAA. Private industry was represented by Atmospherics Inc., Battelle Northwest Laboratories, Human Ecology Research Services, Inc., and Western Scientific Services, Inc