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. A 5-year contract with CSU, Fort Collins, Colorado, for satellite monitoring of cloud systems over the Sierra Nevada. Water and Power awarded a 1-year contract to AS! of Boulder, Colorado, for calibration seeding support during fiscal year 1979, including seeding material releases and data collection and analysis. The UW continued its cloud physics and data collection responsibilities under a long-term contract with Water and Power. Project equipment and techniques were tested during the 1978-79 season. Hypothetical experimental units were identified by the SCPP forecaster based on cloud types. Radar and rawinsonde observations were used to forecast the weather for operational days. The project's seeder aircraft penetrated selected clouds and seeded them with silver iodide and dry ice on a randomized basis. The university's specially instrumented King Air cloud physics aircraft measured the seeding effects and tracked seeding plumes from silver iodide generators operated by other seeding projects in the area. The King Air searched for seedable regions in clouds by measuring and recording liquid water contents and ice crystal concentrations. , On the ground, the SCPP expanded its precipitation gage network to 80 gages, including those operated by private utilities, county governments, and NWS in and near the SCPP study area. Other instrumentation included three AESOP's which measured and recorded precipitation, windspeed and direction, humidity, and temperature. Three ice nucleus counters measured ice nucleus concentra- tions at ground level and ground microphysics studies were conducted to record ice and water concentrations. Project scientists installed a network of high-volume filter samplers and snow samplers to measure contamination from nearby seeding projects of the SCPP study area. The samplers measured silver iodide concentrations tagged with tracer chemicals. Preliminary evaluation of data collected thus far indicates that high ice crystal concentrations, low liquid water contents, and moderate vertical wind velocities generally characterize Sierra storms at temperatures colder than o oC. However, results differ considerably when storms are separated into individual cloud types. The exploratory phase of the SCPP will proceed ostensibly through a series of subphases to reflect the rate of progress in understanding the many cloud types over the study area. Each cloud type would undergo data collection and analysis and would enter the exploratory phase of the project as knowledge became sufficient. The following major design decisions were made during the fiscal year 1979 period based on recommendations by SCPP design contractor, NAWC. . A second year of calibration studies was judged necessary to develop the draft project design. 26