Precipitation Precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation include drizzle, rain, sleet, snow, graupel and hail. Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor, so that the water condenses and "precipitates". Thus, fog and mist are not precipitation but suspensions, because the water vapor does not condense sufficiently to precipitate. Two processes, possibly acting together, can lead to air becoming saturated: cooling the air or adding water vapor to the air. Precipitation forms as smaller droplets coalesce via collision with
David Sleet David Sleet David A. Sleet is an American scientist recognized for championing the application of behavioral science to unintentional injury prevention and helping to establish injury prevention as a global public health concern. He has published hundreds of articles and book chapters and was co-editor of the Handbook of Injury and Violence Prevention.; Injury and Violence Prevention: Behavioral Science Theories; Derryberry’s Educating for Health; and the international prize-winning World Report on Road Traffic Injury Prevention. In 2016, Dr. Sleet retired from the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia where he served as the Associate Director for