Impact of Low-Pressure Systems on Hydrometeorological Conditions at the Sea Coast of the Kaliningrad Region (Baltic Sea) and Examples of Damage of Coastal Constructions in Autumn–Winter 2023–2024

The autumn–winter period 2023–2024 was characterized by high storm activity in all European waters. We report an analysis of the characteristics of a series of cyclones that passed over the southeastern Baltic Sea in the autumn–winter season 2023–2024. Each year has its own features that influence the characteristics of cyclones: the start of the storm period, the track of the cyclone and its depth, the duration of the cyclone impact and the "windows of good weather". These factors must be taken into account when assessing the causes and intensity of coastal damage in order to select coastal protection measures. Data on the synoptic situation (air pressure and temperature, precipitation, height of maximum waves) at offshore and onshore weather stations in the Kaliningrad region revealed an early start (beginning of October) of the storm season. The analysis of the data of the last two decades explains that such an early start in autumn 2023 is an expression of the general regional trend. October 2023 was the stormiest (by gale duration) month during studied period. HYSPLIT backward trajectory calculation model revealed that a characteristic feature of the study period was that most of the cyclones arrived on a westerly trajectory. Such a trajectory is not as destructive for the studied coasts as northern "diving" cyclones. However, cyclones coming from the west, at different stages of their development, affect both the western and northern coasts. Northern cyclones destroy only the northern coast. The increased construction of coast protection on the northern coast of the Sambia peninsula also contributes to the stability of the coastal zone. However, the materials used in coastal protection structures (particularly geotextiles) enter the marine environment after storms and become pollutants. Numerous releases of significant amounts of mega/macro/meso/micro debris, predominantly plastic, into the marine environment have been observed through photo monitoring.