This collaborative case study research effort will focus on the period of March 1 to July 31 of 1997 in the Western and Central Montana regions. For both operational and forecast settings, LDAS-Mosaic LSM variables that will be used in Reclamation’s water resource and river management support tools will be tested and evaluated. For the operational setting, Mosaic output, forced with both observation and NCEP Eta model forecast data, will be compared with Reclamation’s Hydromet/Agrimet data to perform a statistical evaluation of the model data and establish a benchmark to test the forecast simulations against. SWE estimates will be based on NRCS Snotel data and the NWS’s National Operational Hydrologic Remote Sensing Center data. Reclamation’s WSR-88D precipitation accumulation algorithm will be used with archived Level III data to improve estimation of SWE distributions and snow cover, and to identify rain on snow events. The 40-km short-range (24 and 48 hour) Eta model forecast data are also used to drive Mosaic, and the model output will be evaluated as input for the software used by water resource managers. The model variables including snow depth and cover, soil moisture near the surface and in subsequent layers below, and evaporation, will be examined along with forcing variables such as precipitation and surface temperatures, all critical ingredients that set up the flooding conditions in this case study.