South America’s stray hurricane
People in Brazil aren't used to hurricanes, to put it mildly. In fact, no hurricane had ever been reported there until 28 March 2004, when a mysterious system packing winds up to 137 km/hr (85 mph) swept onto the coast of Santa Catarina province. Forecasters from Brazil and from the US National Hurricane Centre had been tracking the storm by satellite. Although no tropical cyclones had ever been officially recorded in the South Atlantic, the swirl of clouds had the clear eye and other telltale features of a bona fide hurricane. Despite the absence of a precedent, Brazil's meteorological service issued warnings and got people out of harm's way. The storm ended up destroying many hundreds of coastal homes, but only one death was reported.
Christened Hurricane Catarina for its landfall location the storm continued to stir things up even after it died. Some meteorologists questioned whether it was truly a hurricane. Many global-change activists pointed to Catarina as an illustration of a planet gone awry. In fact, it turns out that Catarina had some of the classic earmarks of a hurricane, but not all of them. For instance, the showers and thunderstorms circling its centre were more shallow than usual. And Catarina can't easily be pinned on climate change, because the waters over which it formed were actually slightly cooler than average for that time of year. The storm was clearly unprecedented in its landfall impacts, but analysts poring over satellite records found at least one similar (if weaker) system in 1994 that stayed well out to sea. In short, Catarina remains a cipher – a bizarre weather event that pushed the buttons of a world increasingly jittery about climate change.