Accretion (meteorology) Accretion (meteorology) Accretion is defined as the gradual collection of something over time. In meteorology or atmospheric science it is the process of accumulation of frozen water as precipitation over time as it descends through the atmosphere, in particular when an ice crystal or snowflake hits a supercooled liquid droplet, which then freeze together, increasing the size of the water particle. The collection of these particles eventually forms snow or hail in clouds and depending on lower atmosphere temperatures may become rain, sleet, or graupel. Accretion is the basis for cloud formation and can also be seen as water accumulates
Cross country running autumn and winter, and can include weather conditions of rain, sleet, snow or hail, and a wide range of temperatures. Cross country running is one of the disciplines under the umbrella sport of athletics, and is a natural terrain version of long-distance track and road running. Although open-air running competitions are pre-historic, the rules and traditions of cross country racing emerged in Britain. The English championship became the first national competition in 1876 and the International Cross Country Championships was held for the first time in 1903. Since 1973 the foremost elite competition has been the IAAF World Cross Country