Author(s): Wojciech Majewski
Linked Author(s): Wojciech Majewski
Keywords: No Keywords
Abstract: Poland is the country of a relatively mild climate. More severe conditions appear in the north-east region with many lakes, where even low temperatures do not cause important ice problems. There were, however, in the past winters with very low air temperatures and significant ice cover resulting in many difficulties in navigation, hydropower, industrial and municipal water intakes and flooding. Recently meteorological changes especially during winters are observed. Last 5 winters were very mild practically without ice cover on rivers. It is difficult to state whether this is a long-term climatic variation or steady change due to "greenhouse effect". Before this warm period, winters in Poland were characterized by the appearance of one, two or even three "ice periods" which were devided by warmer spells during which there was melting of ice and snow, break-up and even ice-run. Formation of ice jams was usually observed twice in Poland i. e. in the beginning of winter during December-January with tendencies for frazil jams (hanging dams) and in spring (March-April) during ice-run. Existance of several "ice-periods" hinders the operation of ice-booms. Spring ice-run on two main Polish rivers-Vistula and Oder is difficult because their flow direction is from south to north. When in the southern regions ice break-up and ice-run begins, in the north, rivers have still solid ice cover. This causes the necessity of using icebreakers to facilitate ice flow to the sea. Severe ice problems and flood danger appear in the estuarine sections of Vistula and Oder where the influence of Baltic Sea is very important.
Year: 1992