Breakup of River Ice

the process of destruction of the ice cover that occurs because of the action of heat and mechanical forces resulting from an intensive influx of water. In bodies of water (lakes, reservoirs, and ponds) the ice cover that breaks up is either carried out into rivers or thaws in place. On rivers, destruction of the ice cover leads to displacement of the ice downstream—that is, drifting ice. In the European part of the USSR the ice in rivers that flow from north to south (the Volga, Don, and Dnieper) begins to break up in the lower course, and the process gradually shifts upstream, so that there is drifting ice for a long period of time. In Siberia the ice in rivers that flow from south to north (the Ob’, Enisei, and Lena) begins to break up in the upper course and often causes the formation of ice jams in the lower course.