Portugal: Rare ‘Tsunami Cloud’ Phenomenon Sweeps Coastlines

A rare meteorological phenomenon recently took place along the coast of Portugal, captivating hundreds of tourists who rushed to record the event on their phones. The footage of the so-called “tsunami cloud” quickly spread across social media platforms, flooding the internet within hours. In reality, it was an arcus cloud — a rolling, horizontal cylinder-like formation with uneven edges that managed to cover several cities in central and southern Portugal. Arcus clouds typically form when sea breezes meet warmer air masses and often serve as a warning sign for severe thunderstorms. While not considered dangerous, they offer a breathtaking visual spectacle for those lucky enough to witness them. Videos captured from Torreira Beach and other coastal locations show the mesmerizing movement of the cloud, drawing comparisons to a wave in the sky.