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
Global storm activity of 2008 States, eastern Quebec and the Canadian Maritimes with heavy snow, and high winds along the coast. Several areas across Maine, New Brunswick received snow amounts in excess of with as much as locally across the Gaspe region. A low pressure system moving northward up the East Coast caused snow and rain to overspread the Mid-Atlantic region on January 17 and 18. Many spots started off as snow, with a gradual changeover to sleet, freezing rain and then finally rain as the storm slowed down. The greatest concern for accumulating ice was in western North Carolina, while the greatest accumulations of