30 
Negative Surges in the Southern Baltic Sea 
5. Most severe negative 
surges on the southern 
Baltic Sea coast 
5.1. November 1956 
Meteorological situation 
On 24 November 1956, while the Baltic Sea still 
was under the influence of a weak high-pressure 
ridge, a wide low-pressure trough over the 
Norwegian Sea travelled southeast, crossing the 
western part of Scandinavia. The southern Baltic 
Sea coasts were governed by an initially weak, 
later moderate westerly air flow which backed 
SW in the late evening, increasing gradually to 
7 Bft. On 25 November, the trough - still tracking 
eastward - deepened considerably. The SW-S 
storm reached 8-10 Bft in the whole Baltic Sea 
region. As the cold front tracked across the 
western and central parts of the southern Baltic 
coasts in the late hours of this day, the 8-9 Bft 
storm veered W-NW, slowly abating later. 
Hydrological response of sea level 
Sea levels remained just under 500 cm until the 
afternoon of 24 November. In the late hours of 
24 November, the trough reached the Baltic Sea 
and the southern coasts came under the influ 
ence of increasing westerly winds, which gradu 
ally veered SW and S, causing sea levels to fall 
until they reached their minimum values in the 
late hours of 25 November. The minima occurred 
nearly simultaneously along the entire southern 
Baltic coast. Minimum values of 342, 365 and 
383 cm were recorded in Wismar, Warnemünde 
and Sassnitz, respectively, at 18 UTC, and in 
Swinoujscie and Kotobrzeg at 20 UTC, with 
values of 401 and 393 cm, respectively. 
In the night of 26 November, when the storm 
front had passed, the stormy winds backed west, 
later northwest. Sea levels responded immedi 
ately and began to rise, reaching values close to 
or slightly above 500 cm as early as the morning 
of 26 November. 
Fig. 5.1. a Pressure pattern and wind field over the Baltic Sea on 25 November 1956 at 12 UTC