Calvo‐Sancho et al. (2026) Human-induced climate change amplification on storm dynamics in Valencia’s 2024 catastrophic flash flood

Identification

• Journal: Nature Communications
• Year: 2026
• Date: 2026-02-17
• Authors: Carlos Calvo‐Sancho, Javier Díaz-Fernández, Juan Jesús González-Alemán, Amar Halifa‐Marín, M. Miglietta, G. Arguedas, Andreas F. Prein, Ana Montoro-Mendoza, Pedro Bolgiani, Ana Morata, María Luisa Martín
• DOI: 10.1038/s41467-026-68929-9

Research Groups

• Department of Applied Mathematics, Faculty of Computer Engineering, Universidad de Valladolid, Valladolid, Spain
• Centro de Investigaciones sobre Desertificación, Consejo Superior de Investigaciones Científicas (CIDE, CSIC-UV-GVA), Climate, Atmosphere and Ocean Laboratory (Climatoc-Lab), Moncada, Valencia, Spain
• Spanish State Meteorological Agency (AEMET), Department of Science, Madrid, Spain
• Instituto Pirenaico de Ecología, Consejo Superior de Investigaciones Científicas (IPE-CSIC), Zaragoza, Spain
• Laboratorio de Climatología y Servicios Climáticos (LCSC), CSIC-Universidad de Zaragoza, Zaragoza, Spain
• National Research Council of Italy, Institute of Atmospheric Sciences and Climate (CNR-ISAC), Padua, Italy
• Institute of Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland
• Consejo Superior de Investigaciones Científicas (CSIC), Instituto de Geociencias (IGEO), Madrid, Spain
• Department of Earth Physics and Astrophysics, Faculty of Physics, Complutense University of Madrid, Madrid, Spain
• Interdisciplinary Mathematics Institute, Universidad Complutense de Madrid, Madrid, Spain

Short Summary

This study uses a kilometer-scale pseudo-global warming storyline approach to attribute the catastrophic October 2024 Valencia flash flood to anthropogenic climate change, finding that present-day conditions significantly amplified rainfall intensity and the event's overall severity through enhanced moisture and convective processes.

Objective

• To quantify the contribution of anthropogenic climate change (ACC) to the intensity, spatial extent, and underlying physical mechanisms of the catastrophic October 2024 Valencia flash flood event using high-resolution simulations and sub-daily observations.

Study Configuration

• Spatial Scale: Convection-permitting simulations with 1 km horizontal grid spacing over the Valencia region, nested within a 3 km domain.
• Temporal Scale: The study focuses on the October 2024 flash flood event, simulated over a 36-hour period (28-29 October 2024), with analysis concentrated on a 13-hour storm period (29 October 04:00-16:00 UTC). Climate perturbation signals were derived from CMIP6 GCMs comparing 1850–1879 (pre-industrial) and 2009–2038 (present-day/future) periods.

Methodology and Data

• Models used: Weather Research and Forecasting (WRF) model v.4.5 (with WRF single-moment six-class microphysics, Yonsei University PBL, Dudhia short-wave, and RRTM long-wave schemes). Climate perturbation signals derived from 15 CMIP6 Global Climate Models.
• Data sources: Hourly precipitation observations from 256 weather stations (Spanish Meteorological Agency - AEMET, Valencian Meteorological Association - AVAMET, SISRITEL). ERA5 reanalysis data for synoptic conditions and WRF initial/boundary conditions. Meteosat Second Generation satellite data. GADM shape-file data.

Main Results

• Anthropogenic climate change (ACC) increased 1-hour rainfall intensity by 20% per degree Celsius, exceeding Clausius-Clapeyron scaling.
• The 6-hour rainfall rate was intensified by 21% and the area with total rainfall above 180 mm expanded by 55% under present-day conditions.
• The total rain volume within the Jucar River catchment increased by 19% compared to the pre-industrial era.
• This amplification was driven by enhanced atmospheric moisture (11.9% median increase in precipitable water, 8.5% median increase in water vapor flux) and increased atmospheric instability (22.2% median increase in Most Unstable Convective Available Potential Energy - MUCAPE).
• Changes in storm dynamics included a 29.5% median increase in diabatic heating, 11.9% median increase in maximum updraft intensity, and 32.4% median increase in maximum graupel concentration, leading to a 12.6% increase in precipitation efficiency.

Contributions

• Provides a physical-based attribution of a catastrophic flash flood event to anthropogenic climate change using a kilometer-scale pseudo-global warming storyline approach.
• Quantifies the contribution of ACC to sub-daily rainfall intensity and spatial extent, addressing a gap in knowledge often focused on daily scales.
• Offers detailed insights into the underlying physical mechanisms (moisture content, convective available potential energy, updrafts, cloud microphysics, diabatic heating, precipitation efficiency) driving the intensification.
• Utilizes an ensemble of 15 CMIP6 GCMs for climate forcings, enhancing the robustness of statistical analysis and capturing uncertainty compared to single ensemble mean approaches.

Funding

• Grant PID2023-146344OB-I00 (CONSCIENCE) funded by MICIU/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”
• ECMWF Special Projects (SPESMART and SPESVALE)
• Interdisciplinary Mathematics Institute of the Complutense University of Madrid
• Spanish Ministerio de Ciencia, Innovación y Universidades (PRE2020-092343)
• MCI/AEI predoctoral contract (FPU18/00824)
• Next Generation EU, Mission 4, Component 1, CUP B53D23007360006, project “WIND RISK”
• GVA. PROMETEO Grant CIPROM/2023/38
• CSIC-LINCGLOBAL Ref. LINCG24042
• CSIC’s PTI-Clima

Citation

@article{CalvoSancho2026Humaninduced,
  author = {Calvo‐Sancho, Carlos and Díaz-Fernández, Javier and González-Alemán, Juan Jesús and Halifa‐Marín, Amar and Miglietta, M. and Arguedas, G. and Prein, Andreas F. and Montoro-Mendoza, Ana and Bolgiani, Pedro and Morata, Ana and Martín, María Luisa},
  title = {Human-induced climate change amplification on storm dynamics in Valencia’s 2024 catastrophic flash flood},
  journal = {Nature Communications},
  year = {2026},
  doi = {10.1038/s41467-026-68929-9},
  url = {https://doi.org/10.1038/s41467-026-68929-9}
}