23 
2.3.2. Characteristics of the 1986/87 ice season in the areas of Szczecin Lagoon and 
Pomeranian Bay 
Ice formation in the near-shore areas of Szczecin Lagoon started 24 December and in the 
early January, it was completely frozen over. The ice cover grew steadily first over a period of 
nearly four weeks, reaching its maximum thickness of 30 to 38 cm in the first days of 
February. Between 5 and 20 February the process of ice formation ceased and the ice 
thickness decreased up to 20 cm on 20 February. However, the whole Szczecin Lagoon 
remained ice covered during this mild weather period. 
The second maximum of ice development with level ice thickness up to 50 cm in Szczecin 
Lagoon was observed in the middle of March (Fig. 2.4.). Around 25 March, the ice started to 
recede and on 5 April, Szczecin Lagoon was ice-free. In marginal areas of Szczecin Lagoon, 
the ice cover persisted for 99 days, in the central area for 88 days. 
In the Pomeranian Bay the ice winter began in the first half of January: On the Usedom coast, 
first ice formation was observed on 10 January, in the sea area off Swinoujscie on 12 January. 
The first ice period lasted to 8 February with a maximum of the ice development at the end of 
January. On 28 January, the thickness of coastal fast ice reached the value of 25 cm, farther 
eastwards to the latitude 14°30' E there were fields of close to very close, partly compacted 
and up to 30 cm thick ice. From 9 to 27 February, the Pomeranian Bay was free of ice. The 
maximum ice extent during the second ice period was observed in mid-March: East of the 
islands Riigen and Usedom to about the line Adlergrund - Kolobrzeg, the sea area was 
covered with mostly compact 15-30 cm thick ice (Fig. 2.4.). Also during the second ice 
period, the ice situation in the Pomeranian Bay was determined mainly by continually 
changing winds and currents which kept the ice moving. Offshore ice fields bordering on the 
solid rim of coastal ice largely consisted of drift ice pushed toward the coast of Usedom by 
easterly winds and towards the southern coast of Pomeranian Bay by northerly winds. 
Westerly or southerly winds dispersed the ice fields and pushed them toward the open sea. 
The Pomeranian Bay was not completely ice-free until 28 March. In the sea area off 
Swinoujscie, the ice lasted for 48 days, on the coast of Usedom for 59 days. 
Figure 2.4. Maximum extent of ice cover in Szczecin Lagoon and in Pomeranian Bay in 
strong ice winter 1986/87.