In addition, various authors list other factors which produce, or contribute to, sea level changes: water Erlotinib exchange between the Baltic and the North Sea, riverine discharges into the Baltic, seasonal changes in water density, atmospheric precipitation and evaporation, and seiches (Heyenet al. 1996, Samuelsson & Stigebrandt 1996, Carlsson 1998). On the other hand, tidal effects are irrelevant for sea level changes in the Baltic (Suurssar et al. 2003, 2006, Jasińska & Massel 2007). A particular type of sea level

change is a storm surge. Storm surges and falls are defined as short-term, extreme variations in the sea level. Short-term variations are changes of the sea level recorded within several minutes to a few days. They include sea level oscillations intermediate between wind-generated waves and seasonal sea level changes. The coastal protection services describe a storm surge as a dynamic rise MK0683 in vivo of the sea level above the alarm or warning level, induced by the action of wind and atmospheric pressure on the sea surface. Storm surges have always been of interest to chroniclers and scientists. Therefore, their descriptions, both historical and recent, are numerous. The history of the Baltic Sea and old chronicles of major Pomeranian towns are a treasure trove of information on the type

and effects of disastrous surges. The maximum sea levels during storm surges that caused heavy flooding used to be denoted by the high-water marks painted on old buildings or other objects. The most distinct evidence of storms and disastrous 2-hydroxyphytanoyl-CoA lyase wave activity is visible in the church at Trzęsacz. When built in 1250, the church stood in the middle

of the village, 700 m away from the Baltic shore. By 1868, the church found itself on the edge of a cliff, and after 1900 it gradually began to disappear into the sea. What remains today is a single wall, protected from further destruction by heavy seas. Of all the Polish coastal stations, Kołobrzeg was the site of the absolutely highest sea level (2.22 m above the Normal Null, N.N.), recorded on 13 November 1872. That storm surge was observed in numerous ports of the western Baltic coast where the water rose by as much as 3 m above the mean level. Storms and the associated surges have been described and analysed in numerous publications; the most comprehensive descriptions in the Polish literature are those of Majewski et al. (1983), Majewski (1986, 1989, 1997, a,1998b), Sztobryn et al. (2005, 2009) and Wiśniewski & Wolski (2009). These publications and annual records have served as a basis for a summary of historical data on extreme sea levels along the Polish coast (Table 1). Nineteenth-century and earlier descriptions of floods are mainly of historical importance.