61 
Fig. 6.17.2. Pressure pattern over Europe and wind field over the southern Baltic Sea at 12 
UTC on 21 January 2000 
Hydrological response of the sea level 
On 17 January, under the impact of an onshore storm with a nearly constant wind speed, sea 
levels began to rise along the entire coast: first at the eastern water gauges (Kotobrzeg 
before midnight) and shortly later, at about 04 UTC, in Warnemünde, and about 06 UTC in 
Wismar. While the eastern water gauges recorded a rather uniform sea level increase, sea 
levels farther west showed major oscillations which were caused by a pulsation of the 
pressure gradient over this area and by the more complicated coastline. 
The increase lasted about two days. Culmination was reached at 19 UTC on 18 January in 
Kotobrzeg (600 cm), three hours later in Swinoujscie (600 cm) and Sassnitz (590 cm); the 
maxima in Warnemünde (601 cm) and Wismar (607 cm) were recorded at 02 UTC on 19 
January. Water levels then began to fall rather rapidly in the late hours of 19 January, 
supported by the W - SW gale blowing alongshore and slightly offshore. Especially in the 
western coastal area, the minima dropped as low as 483 cm at about 13 UTC on 20 January. 
The sinking of sea levels in Kotobrzeg lasted only until about 06 UTC, and levels at this 
gauge did not drop below 515 cm. 
Shortly after noon on 20 January, a new phase of rising sea levels began, forced by a W - 
NW gale in the low pressure trough, which changed to a N - NE storm around midnight on 
21 January. This time the rather sharp maximum was reached between 12 UTC and 14 UTC 
in Kotobrzeg, at 596 cm, Wismar at 599 cm, Swinoujscie at 597 cm, and Warnemünde at 
589 cm. Only the maximum at Sassnitz, at 581 cm, was delayed by about 6 hours. During 
these 6 days, a rather high reference level indicator of 545 - 559 cm reflected the 
characteristic conditions on the southern Baltic Sea coasts. Calculated values varied from 
529 cm in the morning of 17 January to 551 cm in the morning of 22 January. 
The first surge lasted 50 - 67 hours, and the second one 32 - 37 hours. 
The mean rate of increase was not very high, fluctuating around 2 cm/h on 17 and 18 
January, and around 3-5 cm/h on 20 and 21 January. In some oscillations, however, 
especially at the western coast, the sea level rose in a very unsteady way: the initial “jump” in 
Wismar, between 06 and 09 UTC on 17 January, exceeded 16 cm/h, and a similar increase 
rate was recorded on 18 January between 10 and 13 UTC; the in-between oscillations were 
smaller.