A tsunami from the atmosphere<\/h2>\r\nThe term sounds contradictory \u2013 yet a meteotsunami is fundamentally different from a classic tsunami. While the latter is caused by earthquakes or underwater landslides, a meteotsunami is triggered by the atmosphere.\r\n\r\nThe cause is usually rapid changes in air pressure associated with thunderstorm fronts or so-called squall lines. If such a pressure wave travels at nearly the same speed as the natural propagation of a water wave, it transfers its energy to the sea surface. Meteorologists refer to this as Proudman resonance.\r\n\r\nThe phenomenon becomes dangerous where elongated bays or narrow harbor basins further amplify the water movement. This creates what is known as a seiche \u2013 a standing oscillation that can raise or lower the water level by more than a meter within a few minutes.\r\n

Why Croatia in particular?<\/h2>\r\nThe eastern Adriatic is considered one of the best-studied meteotsunami regions in the world. Vela Luka on Kor\u010dula, Stari Grad on Hvar, and Mali Lo\u0161inj have been particularly affected for decades. There is even a dedicated Croatian term for the phenomenon: \u0160\u0107iga \u2013 regionally also called Se\u0161.\r\n\r\nThe comparatively frequent occurrence of these events is mainly due to the geography. Many harbor basins act like resonance chambers, in which the water oscillations become further amplified.\r\n

The real danger often comes afterward<\/h2>\r\nMany eyewitnesses only notice the first surge of water. For sport boats, however, the real problem often only begins with the subsequent drop in water level.\r\n\r\nMeteotsunamis usually consist of several oscillations. The water level rises, then drops rapidly, and can rise again shortly after. Strong cross currents develop in the harbors, putting extreme strain on mooring lines and cleats.\r\n\r\nBoats moored with short, tightly set lines are particularly at risk. If the water level suddenly drops, they can effectively be left \"hanging\" from their moorings. If the water then rises again, this risks violent impacts against quay walls or mooring piles.\r\n