635 millimetres in a day: DANA Adam in Oliva, and why these storms come in autumn

London gets roughly 600 millimetres of rain in an average year. Oliva got more than that in a single day.

According to the AVAMET weather network in Valencia, Oliva (La Safor) received 635 millimetres of rain in just over 24 hours on 19 October, 440 of them between midnight and 8am. Nearby Forna (Marina Alta) recorded more than 700 litres per square metre. Spain's weather service, AEMET, called the episode "exceptional" and compared it with the rains of 1987. (articulo14.es, 19 October 2026)

• AEMET described Adam as the first high-impact DANA of the 2026–27 season. On 18 October red warnings were in force for the southern Valencia coast, the northern Alicante coast, and Ibiza and Formentera (more than 90 mm in one hour). (articulo14.es, 18 October 2026)
• The Valencian government declared a level-2 emergency, told people in 145 municipalities to stay indoors, evacuated about 2,000 people from seven campsites, and deployed the military emergency unit (UME). (articulo14.es, 19 October 2026)
• By the evening of 19 October five deaths had been reported in Spain, two of them in Oliva. More than 1,000 people were rescued, and the 112 emergency line received 1,713 calls. (Vozpópuli, 19 October 2026) We have not checked the final figure.

In France, Météo-France issued an orange warning for Haute-Corse for 20 October, with 150–200 mm of rain and gusts of 100 km/h expected. (Corse Net Infos, 19 October 2026) No measured data on what happened in Corsica was found.

An autumn Mediterranean storm: rain pouring from the cloud over the sea. Illustration.

The Spanish abbreviation DANA stands for "isolated depression at high levels"; the popular name is gota fría, "cold drop". In France a similar situation is called an épisode méditerranéen.

The ingredients:

1. A warm sea. At the end of summer the Mediterranean is still warm and releases a lot of heat and moisture.
2. Cold air aloft. A cut-off cold low high in the atmosphere makes the air unstable.
3. Mountains on the coast. Wind pushes the moist sea air against coastal ranges, where it rises, and storms form again and again over the same spot.

The result: hundreds of millimetres of rain on one area in a few hours.

On 29 October 2024 another DANA killed 229 people in Valencia province, 237 including Castilla-La Mancha and Andalusia. Some stations then also recorded more than 700 litres per square metre. (mallorcadiario.com, 29 October 2025)

The two figures given for Oliva (635 mm and "more than 560 l/m²") appear in the same article without explanation. We have not checked the final death toll or measured data for Corsica.

This article is for information only. Sources: AEMET and AVAMET (via the Spanish press), articulo14.es, Vozpópuli, Corse Net Infos, mallorcadiario.com (2024–2026).