Storm surge on the Baltic Sea: First autumn storm surge causes little damage

The first storm surge on the Baltic Sea this autumn caused water levels to rise over the weekend of 17 and 18 October 2026. In some cases, the water levels remained below the forecast figures. The North, Central and South control centres in Schleswig-Holstein reported no call-outs due to the flooding.

Highest water level on Sunday morning

According to the Federal Maritime and Hydrographic Agency (BSH), the water level at Lübeck-Travemünde reached 1.25 metres above mean sea level (MSL). In Flensburg, the level was measured at 1.12 metres, and in Kiel at 1.08 metres. The peak was reached early on Sunday morning. Water levels then began to fall again along the Baltic Sea coast.

No major damage was reported from Mecklenburg-Western Pomerania either. The flood defences were closed in Greifswald. The storm surge did not reach the warning level in Rostock.

An easterly wind is causing water levels to rise in the Baltic Sea

Strong winds can drive large volumes of water towards the coast, where it can build up. The south-western coast of the Baltic Sea is particularly exposed to easterly to north-easterly winds. The local topography of the coastline influences how high the water rises. In bays and fjords, water levels can be higher than on the open coast.

On the North Sea, the strong easterly wind had the opposite effect: water levels there were low. This led to problems with ferry services in Lower Saxony and Schleswig-Holstein on Sunday.

At what point does it become a storm surge?

On the Baltic Sea, a storm surge is officially classified by the BSH as beginning at a water level of one metre above mean sea level. From 1.25 metres, it is classified as a moderate storm surge; from 1.50 metres, as a severe one. A very severe storm surge begins at two metres above mean sea level.

The following illustrates just how differently ports can react to significantly higher water levels: Damage assessment following the 2023 Baltic Sea storm surge with examples from the affected facilities. The incident at that time was significantly more severe and should be distinguished from the current autumn floods.

To help with further trip planning, the the BSH’s current storm surge warnings the relevant official information.

Book recommendation

Weather at sea Ralf Brauner, Boris Herrmann and Hans-Jörg Nafzger explain how weather patterns develop and where boaters can obtain reliable weather information. The book covers areas of high and low pressure, regional weather events, sea states, ocean currents and meteorological trip planning. Numerous diagrams illustrate these relationships.

What impact did the storm surge have on your mooring?