43 
634 cm and 642 cm at 12 and 22 UTC, respectively, which were recorded at Kotobrzeg in the 
central part of the coast. The maxima of 647 cm in Wismar and 628 cm in Warnemünde were 
recorded at the same time: on 30 November at 03 UTC. After the maxima had been reached, 
water levels fell slowly as the wind abated on 30 November. 
During this storm surge, the maximum rate of sea level increase was as high as 25-32 cm/h 
in the central coastal area, and 16-23 cm/h in its western part. 
The alarm levels on all water gauges were exceeded and remained at that level for 9-14 
hours. Relative to the reference level indicator (522 cm at 09 UTC on 29 November), the 
surge lasted from 25 hours in Wismar to 40 hours in Kotobrzeg. 
Fig. 6.9.2. Sea level changes during the storm surge of November 1988 
6.10 December 1989 
Meteorological situation 
On 5 December 1989, the Baltic Sea was on the eastern side of an anticyclone over the 
British Isles, while to the east it bordered on a wide depression over Russia. A moderate to 
strong NW air flow developed over the Baltic Sea. In the night of 5 December, a large 
depression (975 hPa over the Norwegian Sea) began travelling across Scandinavia, passing 
over the Sea of Bothnia to the northern Baltic Sea, where it backed and, deepening 
intensively, moved across Estonia toward Russia. While the depression was on its way east, 
a very active trough with a system of atmospheric fronts, connected with the withdrawing low 
over the Baltic Sea, moved southwards. On 5 December and in the morning hours of the 
next day, this pressure pattern led to an intensive, stormy SW air flow over the whole area of 
the Baltic Sea. 
Around noon on 6 December, a warm front reached the southern Baltic coasts, first its 
eastern and central sections, and several hours later also the western parts. Behind the front 
line, the wind veered W and later NW, increasing to 9 Bft. In the early and late morning hours