The essential role of conditional attribution in understanding complex extreme weather.

In October 2024, Valencia, Spain, suffered extreme rainfall that triggered devastating flash-floods. Within a few hours, rainfall accumulations exceeded typical annual totals, breaking the national record for one-hour rainfall in Spain. This event is considered the most destructive weather-related disaster in contemporary Spain in terms of human and economic losses. Calvo-Sancho et al. show that human-driven climate warming significantly intensified the storm, making the disaster markedly more destructive than it would have been in the pre-industrial era.