DANA de extrema severidad que descargo mas de 490 mm en 8 horas en Chiva (Valencia), provocando una de las peores catastrofes naturales de la historia reciente de Espana.
Mas de 230 fallecidos, decenas de miles de viviendas y vehiculos destruidos, danos superiores a 30.000 millones de euros.
The Valencia DANA is the best illustration of why surface pressure is no measure of danger. A DANA — an isolated depression at high levels — is a pocket of cold air that has detached from the general circulation and sits spinning several kilometres up, with no clear signature at the ground. When that pocket settles over a Mediterranean still above twenty-five degrees in October, the thermal contrast triggers convection that feeds itself. The storms stayed anchored over the same inland districts of Valencia for hours, and the water came down ravines that had been dry for months.
The figures that follow are not estimates and have not been copied from any bulletin: they were computed on ERA5, the European Centre’s reanalysis, at a point representative of the area affected — Chiva, inland Valencia — and compared with the 30 complete years of the series. What matters is not the number but the rank.
| Variable | During the episode | Rank in the series |
|---|---|---|
| Minimum pressure | 1,013.2 hPa | does not particularly stand out in the series of the 262,992 hours measured |
| Maximum 10 m wind | 34 km/h | falls in the most extreme 1 % of the series of the 262,992 hours |
| Rainfall over 4 days | 109.0 mm | is the 4th most extreme of the series of the 10,955 4-day windows |
| Minimum temperature | 14.2 °C | does not particularly stand out in the series of the 262,992 hours |
At this point, what was exceptional about the Valencia DANA was the accumulated rainfall. The other variables stayed within what this place sees with some regularity. To place the rainfall: the wettest 4-day episode recorded at Chiva, inland Valencia in the whole series was 142.5 mm, on 27 October 2024.
ERA5 works with cells of about 28 kilometres and smoothed terrain. It describes the air mass well and allows one storm to be compared with another on the same yardstick, which is precisely what cannot be done with station records that have changed site. What it does not see is the detail: a storm that unloads over one particular ravine is averaged across a cell of 800 square kilometres, and that is why its totals are always lower than those of a well-sited rain gauge. For the official figures of an episode, AEMET is the authority.
Data: ERA5 · Copernicus Climate Data Store, CC-BY licence. Sources and methodology →
