Heavy Rain and Flash Floods: When a Storm Turns Dangerous | RainViewer Blog

TL;DR: A flash flood is not decided by how much rain falls over the day, but by how much water falls in how little time. Germany’s national weather service defines heavy rain by the rate of fall, not by the daily total Back-building, where storm cells keep re-forming over the same spot, is a common trigger for local heavy-rain events Sealed surfaces in cities add to the flash-flood risk on top of the weather itself Older drainage systems frequently hit their capacity limits during today’s heavy-rain events A general severe weather warning for a district says little about whether one particular