Abstract Studies conducted during the past 10–15 years have shown that icings are widespread throughout the world in areas with temperate and extreme climatic conditions. Judging by approximate estimates, the total area of icings fed by groundwater and rivers within the USSR amounts to about 128,000 km2, and their annual volume amounts to 160 km3. The volume of all types of icings on the earth's surface amounts to 1500 km3. Application of nonstandard methods of observation have allowed the authors to identify the physical essence of icing phenomena, to present some general patterns in icing variability in time and space, and to determine their role in the hydrological regime of rivers, in the formation of water resources, and in variations in microclimate, relief of the area, and soils and vegetation. Many problems of major scientific and practical significance emerged over the course of the study. The solution of these problems is possible only through multidisciplinary studies at three levels: local, regional, and global.