EGU General Assembly 2020
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the Creative Commons Attribution 4.0 License.

Towards an integrated index on hydrometeorological risk in coastal Mediterranean Regions

Maria-Carmen Llasat1,2, Tomeu Rigo3, Montserrat Llasat-Botija1,2, Maria Cortès1,2, Joan Gilabert1,2, Anna del Moral1,2, Isabel Caballero1,2, Esther Oliver4, and José A. Jiménez5
Maria-Carmen Llasat et al.
  • 1University of Barcelona, Faculty of Physics, Department of Applied Physics, Barcelona, Spain (
  • 2Water Research Institute (IdRA), University of Barcelona, 08028 Barcelona, Spain
  • 3Servei Meteorològic de Catalunya, 08029 Barcelona, Spain
  • 4Facultat d’Economia i Empresa, University of Barcelona, 08028 Barcelona, Spain
  • 5Laboratori d’Enginyeria Marítima, Universitat Politècnica de Catalunya, BarcelonaTech, 08034 Barcelona, Spain

The Mediterranean region is a hot spot for climate and environmental changes (Cramer et al., 2018). Climate change rates currently observed and expected in future scenarios in this region, exceed the global trends for most variables. Particularly, the average annual mean temperature has risen by 1.4°C since the pre-industrial times and it is expected that it could increase more than 1°C before the end of the century. The Mediterranean coastal zone comprises 75 coastal watersheds and 224 coastal administrative regions, with a total of 46,000 km of coastline.  This coastal zone concentrates about the 50 % of the population of the Mediterranean region while also attracts millions of tourists, supports a large network of infrastructures and, also, supports a large set of coastal and marine ecosystems delivering valuable services.

Regional climatic and geographical characteristics determine the area to be frequently affected by multiple hydrometeorological hazards such as thunderstorms, floods, windstorms and marine storms. These hazards together with the existence of high values at exposure determine the Mediterranean coastal fringe to be highly vulnerable and subjected to a high risk to the impact of extreme events, which will likely be worsened due to climate change (IPCC, 2018). Due to this, long-term planning of these coastal areas requires a proper assessment of their vulnerability and risk. Usually, this has been done by considering these hazards in an independent manner, although it is clear that a more holistic and integrated approach considering their  interdependencies and feedbacks is needed.

Within this context, this work  proposes an integrated risk index to classify the Mediterranean coastal municipalities in terms of their susceptibility to be affected by multiple hydrometeorological hazards, which will be later integrated with a similar index for marine  hazards. The index will be tested for a representative Mediterranean coastal area highly affected by hydrometeorological and marine hazards, the Catalonia and Valencia coastal zone (NE Spanish Mediterranean). The indicators represent different system characteristics determining the expected risk: a) climatic, b) geomorphological and  c) impact and perception components. The selected climatic indicators used have been: return period of precipitation, number of lightning strikes and maximum wind speed. Geomorphological indicators include average slope of the catchment area and surface within the municipality. Socioeconomic indicators have been estimated from the economical compensations paid by the Consorcio de Compensación de Seguros (the National insurance company), number of flood events that have affected each municipality estimated from their impact, and population awareness and social impact measured through analysing response in social media (tweets) to the impact of these hazards. Finally, as a matter of validation, the impact of the last flood events affecting this region is compared with the spatial distribution of the developed index.

This work has been developed in the framework of the M-CostAdapt project (FEDER/MCIU-AEI/CTM2017-83655-C2-2-R) where  the adaptability to Climate Change and natural risks of the Mediterranean coast is analysed by jointly considering natural maritime and terrestrial (hydrometeorological) hazards.

How to cite: Llasat, M.-C., Rigo, T., Llasat-Botija, M., Cortès, M., Gilabert, J., del Moral, A., Caballero, I., Oliver, E., and Jiménez, J. A.: Towards an integrated index on hydrometeorological risk in coastal Mediterranean Regions, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5147,, 2020

Comments on the presentation

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Presentation version 1 – uploaded on 24 Apr 2020
  • CC1: Comment on EGU2020-5147, Francisco Pastor, 29 Apr 2020

    Hi Carme, I hope you are all fine and healthy.

    Congrats on your work and the development of the index. Just one question, from the maps it seems that you applied the index on coastal sites. Why not extend to areas inland?

    Best regards

    • AC1: Reply to CC1, Maria-Carmen Llasat, 03 May 2020

      Dear Francisco

      Thank you for your nice words. Following your recommendation the HMHI index as has been presented here could be also applied inland because it only includes natural meteorological hazards. However, in our case, it is the first part of a compound index that will be merged with a coastal hazard index that will include sea storms. As you know our coastal region suffer from multiple hazards with synergetic effects.

      Thanks again

      Maria Carmen Llasat

      • CC2: Reply to AC1, Francisco Pastor, 04 May 2020

        Dear Carme

        Integrating with coastal hazard risks would be a very good point, especially as we have seen in some recent coastal events in our region. Nice work, congrats.

  • CC3: Comment on EGU2020-5147, Valentina Pivotti, 04 May 2020

    I am working on building a risk index myself and I found your work very inspiring. I have a few questions (too many for the chat):

    • I was wondering about the socioeconomic indicators you are thinking of including, in the presentation you mention the insurance compensation and awareness through Twitter, are there others?
    • are you considering the IPCC AR5 guidance on seeing risk as a combination of hazard, vulnerability and exposure?
    • have you tested other ways to aggregate the indicators for HMHI? and if so, does the resulting map change?

    Thank you for your time!

    Valentina Pivotti

  • AC2: Comment on EGU2020-5147, Maria-Carmen Llasat, 04 May 2020

    Dear Valentina

    Thank you very much for your questions. Socioeconomic factors could be gross domestic product, level of insurance and damages, percentaje of urban/industrial area, news about these hazards.

    We use the UNISDR (2009) definition that distinguish between hazard and vulnerability. Vulnerability also includes exposure.

    We have tested other formulae (in all the cases we have multiplied the class values of the different hazards) to joint the four factors but results were similar.

    Where are you applying your index? Which factors do you consider?


    Maria Carmen

  • CC4: Comment on EGU2020-5147, Valentina Pivotti, 05 May 2020


    Thanks for your answers!

    I'm working in areas around the Indian Ocean and I include many indicators about vulnerability and exposure.