A tsunami hit southern Brazil on September 21 — but there was no earthquake.
Instead, the coastline of Santa Catarina was struck by a rare meteorological tsunami, or meteotsunami, sending seawater surging across beaches, streets, and businesses in a matter of seconds.
The event hit around 6 a.m., affecting Laguna, Jaguaruna, and Imbituba. Security footage from Praia do Cardoso in Laguna shows an almost eerie transformation: dry sand is visible one moment; roughly 20 seconds later, the ocean has swallowed the beach and is rushing toward a waterfront restaurant. See the footage linked here and below.
Fishing boats were ripped from their positions, nets and equipment scattered, streets filled with sand and debris, and water damaged buildings. In Laguna, part of a church wall was knocked down. Fortunately, no deaths or injuries were reported.
One fisherman who witnessed the surge described it bluntly: “The sea came with everything.” Another called it “the ugliest thing in the world.”
So what exactly happened?
Unlike a conventional tsunami, a meteotsunami is not triggered by an earthquake, underwater landslide or volcanic eruption.
Instead, a fast-moving atmospheric disturbance — typically involving abrupt pressure changes and intense winds — pushes on the ocean surface. Under the right conditions, that energy can amplify as it approaches shallow water, producing a sudden rise and rush of seawater that looks remarkably similar to a seismic tsunami.
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Santa Catarina’s Civil Defense said radar, satellite and tide-gauge data showed an intense squall line accompanied by winds of roughly 60 to 90 km/h (37–56 mph) and rapid atmospheric-pressure changes. Officials describe the phenomenon as rare and difficult to predict.
The same volatile weather system also produced a meteotsunami at Capão da Canoa in Rio Grande do Sul earlier that day.
For residents watching the ocean suddenly pour inland, however, the scientific distinction probably mattered little.
It looked — and behaved — very much like a tsunami.
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