The U.S. Bureau of Reclamation (Reclamation) has been engaged in weather modification research since the 1960s, although this research declined significantly in the late 1980s through 1990s. In Federal Fiscal Year (FY) 2002, however, Congress authorized funding of the Weather Damage Modification Program (WDMP) and specified that it be administered by Reclamation. The program received $2M per year in FY 2002 and 2003, but was not funded in FY 2004 and beyond. These monies have supported research in seven states: Colorado, New Mexico, Texas, Nevada, Utah, North Dakota, and Oklahoma. The end goals of WDMP are to increase water supplies at reduced cost and to reduce damage from drought and hail, by addressing current uncertainties and limitations of weather modification. There were three intermediate targets associated with these goals: rainfall augmentation, snowfall augmentation, and hail suppression. States were expected to match federal funding and “piggyback” their research on existing operational weather modification projects. This paper summarizes the science questions, research approaches, and preliminary results for each state project.

A recent National Academy of Science (NAS) report on weather modification research recommended initiation of a sustained national research program. Although the WDMP is not presently funded, the project may serve as a foundation for such a research program with Federal government support. Also according to the NAS report, such research should be pursued because weather modification has the potential for relieving water resource stresses. Reclamation is the major wholesale supplier of water in the U.S. and operates in 17 western states, where such stresses are the most severe, owing in part to a multi-year drought and rapid population growth. As a result, Reclamation is being forced to make increasingly difficult choices regarding water allocation. The WDMP represents the first federally supported attempt in the 21st century to investigate the major, lingering scientific questions about the efficacy of weather modification. Answers to these questions are crucial prerequisites to the use of weather modification to alleviate the burgeoning water supply crisis in the West.