12 
3. FEATURES OF STORM SURGES 
Some characteristic parameters (calculated for each particular storm surge) define the 
features of storm surges threatening the coasts and constitute the basis of the storm surge 
definition provided in chapter 1. 
These parameters include the maximum sea level recorded during the surge and the mean 
daily reference level indicator, which is a highly useful parameter in routine operational 
forecasting. The latter is determined by the surplus (above the multi-year mean sea level) of 
surface water accumulated off the southern coast. Other important parameters are the 
duration (persistence) of the high levels, and the persistence of levels above the warning and 
alarm levels (560 cm and 580 cm at Swinoujscie). 
3.1 Maximum sea levels 
The highest sea levels in the area under review were observed during storm surges; the 700 
cm level was exceeded at the Wismar station in November 1995, at a level of 702 cm. During 
the same storm, Swinoujscie (661 cm) and Warnemünde (660 cm) reported the highest 
levels of the 1976-2000 period. By contrast, the highest level in Sassnitz was observed in 
January 1992, at 636 cm, and in Kotobrzeg in November 1988 (642 cm). 
frequency in % 
—N> N> CO 
О СЛ О СЛ О СЛ О 
Г 
II 
n 
II 
1 
I 
1 
1 
r 
ln 
1 
■ 
■ 
550 560 570 580 
590 600 610 620 630 640 650 660 670 680 
maximum sea level in cm 
690 700 710 
■ Wismar DWamemünde DSassnitz 
Fig. 3.1. Frequency distribution of maximum sea levels observed during storm surges at 
Wismar, Warnemünde and Sassnitz in 1976-2000 
The frequency distribution of maximum sea levels (analysis of sea levels at the German 
stations in 1976-2000) is presented in Fig. 3.1. Maximum sea levels (during storm surges) at 
the Wismar station were observed most frequently (about 20%) in the 610-620 cm range. At 
Warnemünde, about 21% of maximum levels were within the 590-600 cm range. At Sassnitz, 
up to 52.1% of the maximum sea levels ranged between 570 and 590 cm. 
The frequency distribution of maximum sea levels (reported at Swinoujscie and Kotobrzeg 
during storm surges in 1976-2000) is presented in Figs. 3.2. and 3.3., in comparison with the 
1950-1975 period. In both periods, i.e. 1950-1975 and 1976-2000, the maximum sea levels 
ranged mostly from 570-590 cm; at Swinoujscie, the percentage was 48% in the former 
period and 52% in the latter, compared to about 53% and 49%, respectively, at Kotobrzeg. At