Response of hydrological characteristics for local coastal water bodies of the South-Eastern Baltic to extreme weather events in autumn–winter 2023/2024

Abstract A total of 25 storms were recorded in the autumn-winter period of 2023–2024, with eight of these exhibiting a notable impact on the coast of the South-Eastern Baltic. As a consequence of this phenomenon, the western coast of the Sambian Peninsula of the Kaliningrad Oblast (Russia) was subjected to devastating effects: partial washout of the beach, flooded recreational infrastructure, the direction of the water flow changed and the formation of a local canyon, the dam of a flooded quarry broke through and was completely destroyed. The methodology for the integrated use of field measurement data, meteorological and hydrological information, re-analysis data, as well as satellite images was developed in order to analyses the effects of storms on inland coastal water bodies. Almost all storm events caused sea levels to rise, which had a devastating effect on the coast. As a consequence of the initial storm in October 2023, the inland water body was entirely obliterated, first becoming part of the sea and then a sandy beach. The most significant event was a series of storms in January and February 2024, which resulted in a 90 cm increase in the level rise relative to the pre-storm period. The storms brought with them a vast amount of precipitation, amounting to 51% of the total during the cold period. Rising sea levels and heavy precipitation caused the flooding of coastal lagoon lakes, changes in their thermohaline and oxygen regimes, as well as flooding of adjacent infrastructure.