Storm Filomena was a extratropical cyclone in early January 2021 that was most notable for bringing unusually heavy snowfall to parts of Spain, with Madrid recording its heaviest snowfall in over a century [1], and with Portugal being hit less severely. The eighth named storm of the 2020–21 European windstorm season, Filomena formed over the Atlantic Ocean close to the Canary Islands on 7 January, subsequently taking a slow track north-eastwards towards the Iberian Peninsula and then eastwards across the Mediterranean Sea.