control cells. Unpublished results of a randomized experiment in Lanzhou Province of China were similarly inconclusive. These results raise further questions about the validity of the continuing Soviet claims of damage reductions of 70 to 90% from operational This paper is not subject to U.S. copyright. Pub-programs (Burtsev, 1980). Recent evaluations of lished in 1983 by the American Geophysical Union. an operational program in Bulgaria (Stanchev and Simeonov, 1981) show considerably smaller damage Paper number 3R0543. reductions (54-60%) with large variability from 1065 066 Dirks: Progress in Weather Modification Research year to year. Suppression effectiveness, in the Bulgarian data, appears to decrease with increased storm intensity. Analysis of the NHRE data is expanding our knowledge of hailstorm processes and many new results are summarized in a recent two-volume