Storm tides represent a major environmental threat. At sea, wind drags water masses towards the coasts, where the water levels may become dangerously high, overwhelm coastal defenses, and inundate low-lying coastal areas. In 1953 and 1962 two major storm tide disasters occurred along the North Sea coast. Both flooded several thousand hectares of land and were associated with significant death toll and injuries. Since then, coastal defenses in low-lying areas have been improved substantially.

In more recent years and for parts of the German North Sea coast even higher storm tides were observed. Contrary to the devastating events from 1953 and 1962, the new record heights caused no severe damages due to significantly improved coastal protection. Due to the latter, public perception of storm tide vulnerability and risk has decreased in recent years.

In order to make up a storm tide several meteorological and oceanographic factors must work together. EXTREMENESS will investigate the interplay between these factors to identify combinations that may lead to storm tides that are highly unlikely but still physically possible and plausible and which may cause extreme damages or have extreme consequences.

Based on an extensive and existing data base consisting of observations, reanalysis and met-ocean hindcast data together with information from climate change scenarios EXTREMENESS will identify such events, describe them in detail and study conditions that bear the potential for further amplification of such events. This will include, for example, effects and contributions from rising mean sea levels or the timing between the tide and the peak of the storm.

For the most extreme cases and together with regional actors engaged in coastal protection a transdisciplinary assessment will be made and, in a thought experiment, possible consequences for future coastal protection and adaptation will be considered and assessed.