Page "Baltic Sea" Paragraph 16

It is known that since 1720, the Baltic Sea has frozen over entirely only 20 times.

The most recent case was in early 1987, which was the most severe winter in Scandinavia since that date.

The ice then covered 400 000 km < sup > 2 </ sup >.

During the winter of 2010 / 11, which was quite severe compared to those of the last decades, the maximum ice cover was 315 000 km < sup > 2 </ sup >, which was reached on 25 February 2011.

The ice then extended from the north down to the northern tip of Gotland, with small ice free areas on its either side, and the east coast of the Baltic Sea was covered by an ice sheet ca.

wide all the way down to Gdańsk.

This was brought about by a stagnant high-pressure area that lingered over central and northern Scandinavia from ca.

10 to 24 February.

After this, strong southern winds pushed the ice further into the north, and much of the waters north of Gotland were again free of ice, which had then packed against the shores of southern Finland.

The effects of the afore-mentioned high-pressure area did not reach the southern parts of the Baltic Sea, and thus the entire sea did not freeze over.

However, floating ice was additionally observed near Świnoujście harbour in January 2010.