A heavy rainstorm in Catalonia, Spain in October 2019 caused a devastating flash flood that led to six deaths. The researchers studied the weather conditions that caused the flood, including moisture from the southeast and local geography that triggered intense rain. The dry soil made the flooding worse. The flood happened quickly, giving little time for warnings. The researchers also looked at how quickly people responded to the flood and compared it to the weather conditions. They suggest ways to improve warnings and preparedness for future floods.