46 
Negative Surges in the Southern Baltic Sea 
November 1985 
— Wismar —•—Warnemünde Sassnitz <■ - Swinoujscie — —Kotobrzeg ■ MSL 
Fig. 5.11. b Variations of sea level decrease during the storm of 6 November 1985 
5.12. January 1990 
Meteorological situation 
An active low pressure centre originating in the 
area southeast of Greenland travelled eastward 
on 24 January and reached northern Ireland on 
25 January. As it continued tracking east, the cen 
tre deepened over the North Sea until it reached its 
lowest pressure of 949 hPa at 18 UTC on 25 Janu 
ary. Around noon on 26 January, the centre was 
over southern Scandinavia, and early on 27 Janu 
ary it reached southern Finland (Fig. 5.12. a). 
The depression centre approaching from the Brit 
ish Isles and tracking toward southern Finland 
was preceded by a field of a very steep pressure 
gradient. The low was accompanied by initially 
moderate southwesterly winds which in the rear 
of the cold front veered temporarily and later 
reached gale force. In the afternoon of 25 January, 
as a southwesterly hurricane of 11—12 Bft devel 
oped over the English Channel and the southern 
coasts of the North Sea, an easterly storm of 
9-10 Bft hit the southwestern coasts of Norway. 
Behind the colt front, in the early hours of 26 Jan 
uary, the hurricane raged across eastern England 
(NW-W winds of 9-10 Bft), the southern North 
Sea region and coasts (SW hurricane of 12 Bft), 
Denmark (SW backing hurricane of 10-11 Bft), 
and the western and southern areas of the Baltic 
Sea (SW hurricane of 9-11 Bft, veering slightly). It 
was not until the late hours of 26 January that the 
storm began to abate, although in the morning of 
27 January winds on the southern Baltic Sea 
coasts locally still gusted up to 7-8 Bft. 
Hydrological response of sea level 
In the early hours of 26 January, sea levels oscil 
lated above the mean values. Very soon, however, 
between 03 and 07 UTC, as the frontal system 
quickly traversed the area, sharp disturbances in 
the direction of the W-SW hurricane passed along 
the southwestern coast. Rapid water level 
decreases of short duration were the first 
response. Between 03 and 04 UTC, the rates of 
decrease were as high as 50 cm/h in Wismar and 
about 35 cm/h in Swinoujscie (Fig. 5.12. b). The 
other gauges recorded this event between read 
ings. The decrease was followed by a short-last 
ing increase of levels between 04 and 07 UTC 
due to veering wind behind the cold front. In the 
next hours, when the hurricane again changed 
direction from nearly alongshore to offshore, 
water levels fell to very flat minima between 17 
and 22 UTC in the western part of the coast, and 
between 17 UTC on 26 January and 02 UTC on 
27 January further east. The lowest value of 
335 cm was recorded on 26 January at 16 UTC in 
Wismar, where water levels remained below 
340 cm for 6 hours. On 26 January, Warnemünde 
recorded a minimum of 375 cm at 19 UTC, Sass 
nitz 418 cm at 16 UTC, Swinoujscie 415 cm at 
19 UTC, and Kotobrzeg 461 cm at 17 UTC.