6 
Figure 1.3. Ice conditions of Dziwnow, sea area, period 1961 - 1990 
(There are no data for the winters 1960/61, 61/62, 62/63 and 63/64) 
1.1. Ice conditions 
The annual data on ice conditions in Szczecin Lagoon and Pomeranian Bay in the 30-year 
period 1961-1990 are presented in Table 1.2. The table contains the ice parameters: number 
of days with ice, duration of ice season, date of first ice, date of last ice, maximum ice 
thickness (if available), maximum ice concentration or maximum ice extent (if available) 
for each observation station independent of ice origin. 
Ice winters of different degrees of severity occurred in the period under consideration. In mild 
winters, small amounts of thin ice were observed for a few days in the coastal areas of 
Szczecin Lagoon, while the central part and the Pomeranian Bay remained ice-free. In very 
severe winters, ice covered the entire Szczecin Lagoon for up to 130 days (Figure 1.2). About 
100 days with ice are recorded in very severe winters in the Pomeranian Bay. Even during 
severe winters, ice-free periods occur in the sea areas. Therefore, the number of days with ice 
may be smaller than the duration of the ice season (Figure 1.3). In the shallow bays, this 
difference is not so large. The maximum ice thickness varies from 5 to 60 cm in Pomeranian 
Bay, and from 10 to 100 cm in Szczecin Lagoon depending on the severity of the winter.