Seedability of Winter Orographic Storms in Utah

The primary objective of this research has been to collect and analyze data from (randomized) seeded and unseeded winter storms over the Wasatch Mountains for the purpose of developing and designing cloud seeding technology. Two field programs were conducted sequentially; the first was done by airborne seeding and the second by seeding from mountaintop generators. Analysis of precipitation estimators based upon radar and/or rawinsonde data and target precipitation show that increased precipitation due to seeding may occur under certain meteorological conditions. Favorable conditions were found when the supercooled water concentration as measured by aircraft icing rates was high. Precipitation in these particular seeded storms was several times the amount estimated from relationships derived from meteorological parameters and unseeded precipitation. Based upon thes