Ice Thrusting and Hummocking on the Shores of the Southern Baltic Sea's Coastal Lagoons

Abstract

ABSTRACT Girjatowicz, J.P., 2014. Ice thrusting and hummocking on the shores of the southern Baltic Sea's coastal lagoons. This study concerns hydrological and meteorological conditions during which ice thrusting and hummocking events were observed on the shores of the Szczecin and Vistula Lagoons. The author documented four events of extensive (over distances longer than 100 m) onshore ice thrust: three thrusting events (1 March 1976, 14 January 1993, and 28 January 2003) in the Szczecin Lagoon and one (8 February 2011) in the Vistula Lagoon. The thrusting sheets of ice were usually 15 to 20 cm thick, and their thrust was associated with a very strong wind. The extensive ice thrusting was facilitated by the flatness of the shore and by a high water level. At low water levels and on steeper shores, the ice becomes hummocked. Ice hummocking close to the shore proceeds in three stages, the second stage being the most important: the sheet of ice coming from the windward side breaks up, under its own weight, ...