Atmospherical Science

A national map of large hailstorms

Paulo Lanzetta Rural areas of the state of Rio Grande do Sul are among the places most heavily affected by the phenomenonPaulo Lanzetta

People living in southern Brazil should keep an eye on the weather in the late afternoons of September and October and be prepared for serious storm-related disruptions. That time of day, especially in early Spring, is when the country experiences its most destructive hailstorms—the kind that tend to damage crops, livestock and buildings and leave people homeless. These storms mainly affect the western and central regions, as well as the coastal strip that runs along the states of Rio Grande do Sul, Santa Catarina and Paraná. The finding comes from a national mapping survey of the most destructive hailstorms (Atmospheric Research, October 21, 2016). In this study, researchers from the Federal Institute of Paraná (IFPR) and the University of São Paulo (USP), in collaboration with colleagues from NASA, did a survey of hailstorms recorded by the National Civil Defense from 1999 to 2012. They identified 1,630 storms and analyzed the distribution of 732 storms on which there were detailed data such as time of day, location, and extent of damage. On-site recording is important for confirming satellite maps and correcting climate forecasting models. The map confirms that southern Brazil is one of the planet’s major hailstorm hotspots.