Forms of Onshore Ice Thrusting in Coastal Lagoons of the Southern Baltic Sea

Abstract

Hydrometeorological conditions of ice field onshore thrusting and its forms were explored in the Szczecin and Vistula lagoons. Five well-documented cases of ice sheet thrusting to more than 100 m inland are presented. Four cases (March 1, 1976; January 14, 1993; January 28, 2003; and February 1, 2004) were observed in the Szczecin Lagoon, one (February 8, 2011) occurring in the Vistula Lagoon. In both areas, the ice field onshore thrusting was driven mainly by strong winds following a cold front in a deep baric low. The longest thrusts, several to 150-m wide, pushed the ice sheet 140 m inland. Near the shore, the sheets were alternated by ice hummocks. The ice sheet base was usually flanked by elongated, low ice piles. The ice sheet tapered inland, its edges rounding off. The thrust ice sheets were finger, tongue, half-ellipse, or semicircle shaped, and they were distinctly rounded in the frontal part.