Extraordinary 2021 snowstorm in Spain reveals critical threshold response to anthropogenic climate change

This study investigates the exceptional January 2021 snowfall event in Spain (Filomena) to determine the influence of anthropogenic climate change (ACC). Using observational data and flow analogs, the study shows that the synoptic pattern leading to Filomena hasn't significantly changed in frequency. An atmospheric model and storyline attribution approach were used to assess ACC's impact on the event's thermodynamics. Results indicate that ACC intensified snowfall in northern highlands by up to +40% compared to pre-industrial conditions, while weakening it by up to -80% in nearby southern lowlands. This contrasting response is defined by a critical temperature threshold, which would be further enhanced by the end of the 21st century.

Damián Insua-Costa, Marc Lemus-Cánovas, Juan J. González-Alemán, Martín Senande-Rivera, María del Carmen Llasat, Gonzalo Miguez-Macho, Diego G. Miralles