Précipitations exceptionnelles et crues-éclair dans l'aire pyrénéo-méditerranéenne / High intensity rainfalls and flash floods into the Mediterranean Pyrenees

Abstract. This paper describes an integrated, high-resolution dataset of hydro-meteorological variables (rainfall and discharge) concerning a number of high-intensity flash floods that occurred in Europe and in the Mediterranean region from 1991 to 2015. This type of dataset is rare in the scientific literature because flash floods are typically poorly observed hydrological extremes. Valuable features of the dataset (hereinafter referred to as EuroMedeFF database) include i) its coverage of varied hydro-climatic regions, ranging from Continental Europe through the Mediterranean to Arid climates, ii) the high space-time resolution radar-rainfall estimates, and iii) the dense spatial sampling of the flood response, by observed hydrographs and/or flood peak estimates from post-flood surveys. Flash floods included in the database are selected based on the limited upstream catchment areas (up to 3000 km2), the limited storm durations (up to 2 days), and the unit peak flood magnitude. The EuroMedeFF database comprises 49 events that occurred in France, Israel, Italy, Romania, Germany, and Slovenia, and constitutes a sample of rainfall and flood discharge extremes in different climates. The dataset may be of help to hydrologists as well as other scientific communities because it offers benchmark data for the identification and analysis of the hydro-meteorological causative processes, evaluation of flash flood hydrological models and for hydro-meteorological forecast systems. The dataset also provides a template for the analysis of the space-time variability of flash flood-triggered rainfall fields and of the effects of their estimation on the flood response modelling. The dataset is made available to the public as a "public dataset" with the following DOI: (https://doi.org/10.6096/mistrals-hymex.1493).

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Integrated high-resolution dataset of high-intensity European and Mediterranean flash floods

Earth System Science Data ◽

10.5194/essd-10-1783-2018 ◽

2018 ◽

Vol 10 (4) ◽

pp. 1783-1794 ◽

Cited By ~ 25

Author(s):

William Amponsah ◽

Pierre-Alain Ayral ◽

Brice Boudevillain ◽

Christophe Bouvier ◽

Isabelle Braud ◽

...

Keyword(s):

High Resolution ◽

High Intensity ◽

Flash Flood ◽

Flash Floods ◽

Space Time ◽

Radar Rainfall ◽

Catchment Areas ◽

Flood Response ◽

The Mediterranean ◽

Resolution Dataset

Abstract. This paper describes an integrated, high-resolution dataset of hydro-meteorological variables (rainfall and discharge) concerning a number of high-intensity flash floods that occurred in Europe and in the Mediterranean region from 1991 to 2015. This type of dataset is rare in the scientific literature because flash floods are typically poorly observed hydrological extremes. Valuable features of the dataset (hereinafter referred to as the EuroMedeFF database) include (i) its coverage of varied hydro-climatic regions, ranging from Continental Europe through the Mediterranean to Arid climates, (ii) the high space–time resolution radar rainfall estimates, and (iii) the dense spatial sampling of the flood response, by observed hydrographs and/or flood peak estimates from post-flood surveys. Flash floods included in the database are selected based on the limited upstream catchment areas (up to 3000 km2), the limited storm durations (up to 2 days), and the unit peak flood magnitude. The EuroMedeFF database comprises 49 events that occurred in France, Israel, Italy, Romania, Germany and Slovenia, and constitutes a sample of rainfall and flood discharge extremes in different climates. The dataset may be of help to hydrologists as well as other scientific communities because it offers benchmark data for the identification and analysis of the hydro-meteorological causative processes, evaluation of flash flood hydrological models and for hydro-meteorological forecast systems. The dataset also provides a template for the analysis of the space–time variability of flash flood triggering rainfall fields and of the effects of their estimation on the flood response modelling. The dataset is made available to the public with the following DOI: https://doi.org/10.6096/MISTRALS-HyMeX.1493.

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Extreme Rainfall in the Mediterranean: What Can We Learn from Observations?

Journal of Hydrometeorology ◽

10.1175/jhm-d-12-083.1 ◽

2013 ◽

Vol 14 (3) ◽

pp. 906-922 ◽

Cited By ~ 79

Author(s):

N. Rebora ◽

L. Molini ◽

E. Casella ◽

A. Comellas ◽

E. Fiori ◽

...

Keyword(s):

Extreme Rainfall ◽

Flash Floods ◽

Rain Gauge ◽

Extreme Rainfall Events ◽

Rainfall Events ◽

Life Threatening ◽

The Mediterranean ◽

Moderate Resolution Imaging Spectroradiometer ◽

Ground Effects

Abstract Flash floods induced by extreme rainfall events represent one of the most life-threatening phenomena in the Mediterranean. While their catastrophic ground effects are well documented by postevent surveys, the extreme rainfall events that generate them are still difficult to observe properly. Being able to collect observations of such events will help scientists to better understand and model these phenomena. The recent flash floods that hit the Liguria region (Italy) between the end of October and beginning of November 2011 give us the opportunity to use the measurements available from a large number of sensors, both ground based and spaceborne, to characterize these events. In this paper, the authors analyze the role of the key ingredients (e.g., unstable air masses, moist low-level jets, steep orography, and a slow-evolving synoptic pattern) for severe rainfall processes over complex orography. For the two Ligurian events, this role has been analyzed through the available observations (e.g., Meteosat Second Generation, Moderate Resolution Imaging Spectroradiometer, the Italian Radar Network mosaic, and the Italian rain gauge network observations). The authors then address the possible role of sea–atmosphere interactions and propose a characterization of these events in terms of their predictability.

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DETECTION OF FLOOD IMPACTED AREAS IN EAST NUSA TENGGARA USING SENTINEL-1 IMAGERY

CI-TECH ◽

10.33005/ci-tech.v2i01.31 ◽

2021 ◽

Vol 2 (01) ◽

pp. 37-41

Author(s):

Bagas Aryaseta

Keyword(s):

Cloud Computing ◽

Tropical Cyclone ◽

Data Processing ◽

High Intensity ◽

Flash Floods ◽

Google Earth ◽

Classification Method ◽

Small Signal ◽

Pixel Value ◽

Google Earth Engine

Flash Floods in East Nusa Tenggara occured on April 4th, 2021. These Flash Floods are scattered from East Flores Regency, Lembata Regency, Alor Regency, Malacca Regency, Sabu Raijua Regency, Kupang City, Kupang Regency, and Ende Regency. The cause of these Flash Floods is the high intensity of rain caused by the tropical cyclone Seroja. Mapping of flood locations plays an important role in prevention and mitigation efforts. In this study, InSAR data processing was carried out from the Sentinel 1A satellite to find flood-affected locations in East Nusa Tenggara. 32 images of Sentinel-1 were processed before and 31 images after the Flash Floods incident. The method used is the classification method using cloud computing, Google Earth Engine. The results show that the flood-affected areas can be detected based on a lower pixel value (indicating a very small signal backscatter value), then compared to the conditions before the flood. The four sample points identified, namely points A, B, C, and D each have pixel values of -8.58, -9.99, -12.43, and -9.29 for the VV polarized image, respectively. For VH polarized image is -17.35, -17.96, -17.84, and -14.22, respectively.

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Rainstorms able to induce flash floods in a Mediterranean-climate region (Calabria, southern Italy)

Natural Hazards and Earth System Science ◽

10.5194/nhess-14-2423-2014 ◽

2014 ◽

Vol 14 (9) ◽

pp. 2423-2434 ◽

Cited By ~ 20

Author(s):

O. G. Terranova ◽

S. L. Gariano

Keyword(s):

Mediterranean Climate ◽

Southern Italy ◽

Flash Flood ◽

Temporal Structure ◽

Flash Floods ◽

Rain Gauges ◽

Mediterranean Countries ◽

Preliminary Validation ◽

The Mediterranean ◽

Landslides And Debris Flows

Abstract. Heavy rainstorms often induce flash flooding, one of the natural disasters most responsible for damage to man-made infrastructures and loss of lives, also adversely affecting the opportunities for socio-economic development of Mediterranean countries. The frequently dramatic damage of flash floods are often detected, with sufficient accuracy, by post-event surveys, but rainfall causing them are still only roughly characterized. With the aim of improving the understanding of the temporal structure and spatial distribution of heavy rainstorms in the Mediterranean context, a statistical analysis was carried out in Calabria (southern Italy) concerning rainstorms that mainly induced flash floods, but also shallow landslides and debris flows. Thus, a method is proposed – based on the overcoming of heuristically predetermined threshold values of cumulated rainfall, maximum intensity, and kinetic energy of the rainfall event – to select and characterize the rainstorms able to induce flash floods in the Mediterranean-climate countries. Therefore, the obtained (heavy) rainstorms were automatically classified and studied according to their structure in time, localization, and extension. Rainfall-runoff watershed models can consequently benefit from the enhanced identification of design storms, with a realistic time structure integrated with the results of the spatial analysis. A survey of flash flood events recorded in the last decades provides a preliminary validation of the method proposed to identify the heavy rainstorms and synthetically describe their characteristics. The notable size of the employed sample, including data with a very detailed resolution in time that relate to several rain gauges well-distributed throughout the region, gives robustness to the obtained results.

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Some lessons to improve adaptation measures in basis to the analysis of three extreme rainfall events and its associated impacts in the Spanish Mediterranean Coast.

10.5194/egusphere-egu21-2060 ◽

2021 ◽

Author(s):

Isabel Caballero-Leiva ◽

Montserrat Llasat-Botija ◽

María Carmen Llasat

Keyword(s):

Extreme Rainfall ◽

Flash Floods ◽

Mediterranean Coast ◽

Point Of View ◽

Adaptation Measures ◽

Extreme Rainfall Events ◽

Rainfall Events ◽

Wide Range ◽

The Mediterranean ◽

Short Time

The Mediterranean coast of Spain is well known for its pleasant weather, which results in high population densities and large number of tourists. The littoral area is constituted by a rich variety of ecosystems combined with a well-developed industry and agricultural land. The attractive Mediterranean climate has another side of the story, due partially to the Spanish mountain ranges along the east coast. This results in extreme rainfall events that drive flash floods that carry significant economic, environmental and social impact to the affected areas. The mentioned scenario gets more complex when considering the climate change that is already experienced in the Mediterranean region. Among others, the increase in extreme precipitation events envisioned by global climate models. Considering that storms and flash floods are the highest occurrence and most expensive events, it is fair to analyse the adaptation measures in place for the studied area.The present work shows the comparative analysis of three recent case studies of major compound hazard events happened in the Mediterranean coast of Spain with special focus on littoral impacts and within a short time frame of 4 months: September 2019, October 2019, and January 2020. The nearness of the events left short time for recovery between them, as well as added aggravation due to the accumulated environmental and economic impacts caused to the region and the Covid-19 pandemics. The work presents a wide range of data (meteorological, hydrological, economical, impact data, etc.), collected from the press and social media as well as from official sources such as CCS, Meteorological agencies, Civil Protection, and others. This allows developing a multidisciplinary approach from the point of view of hydrology, meteorology, sea sciences and social science.The analysis of the events is made from a holistic point of view including details as varied as the geographical areas affected up to municipality level, circumstances of casualties, location of extreme hydrometeorological values recorded during the events, environmental impact and economic loss. Furthermore, the different factors driving to each compound hazard event (floods, windstorms, sea surges, ...) and cascade effects have been analysed. Moreover, an analysis of the adaptation measures present at the time is done, along with suggestions of complementary or better adaptation measures for the three cases. Even though the data collection and analysis are made for the entire affected area within the Iberian Peninsula, the impacts and adaptation measures considered in this communication have a focus on the coastal area, including its various littoral ecosystems, coastal infrastructures, tourist sector, etc.This work has been done in the framework of the M-CostAdapt (CTM2017-83655-C2-1&2-R) research project, funded by the Spanish Ministry of Science and Innovation (MICINN-AEI/FEDER, UE).

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Integrated high-resolution dataset of high intensity Euro-mediterranean flash floods

10.5194/essd-2018-42-rc1 ◽

2018 ◽

Author(s):

Anonymous

Keyword(s):

High Resolution ◽

High Intensity ◽

Flash Floods ◽

Resolution Dataset

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Rainstorms able to induce flash floods in a Mediterranean-climate region (Calabria, southern Italy)

Natural Hazards and Earth System Sciences Discussions ◽

10.5194/nhessd-2-2049-2014 ◽

2014 ◽

Vol 2 (3) ◽

pp. 2049-2078 ◽

Cited By ~ 1

Author(s):

O. G. Terranova ◽

S. L. Gariano

Keyword(s):

Mediterranean Climate ◽

Southern Italy ◽

Flash Flood ◽

Temporal Structure ◽

Flash Floods ◽

Rain Gauges ◽

Mediterranean Countries ◽

Preliminary Validation ◽

The Mediterranean ◽

Landslides And Debris Flows

Abstract. Heavy rainstorms often induce flash flooding, one of the natural disasters most responsible for damage to man-made infrastructure and loss of lives, adversely affecting also the opportunities for socio-economic development of Mediterranean Countries. The frequently dramatic damage of flash floods are often detected with sufficient accuracy by post-event surveys, but rainfall causing them are still only roughly characterized. With the aim of improving the understanding of the temporal structure and spatial distribution of heavy rainstorms in the Mediterranean context, a statistical analysis was carried out in Calabria (southern Italy) concerning rainstorms that mainly induced flash floods, but also shallow landslides and debris-flows. Thus a method is proposed – based on the overcoming of heuristically predetermined threshold values of cumulated rainfall, maximum intensity, and kinetic energy of the rainfall event – to select and characterize the rainstorms able to induce flash floods in the Mediterranean-climate Countries. Therefore the obtained (heavy) rainstorms were automatically classified and studied according to their structure in time, localization and extension. Rainfall-runoff watershed models can consequently benefit from the enhanced identification of design storms, with a realistic time structure integrated with the results of the spatial analysis. A survey of flash flood events recorded in the last decades provides a preliminary validation of the method proposed to identify the heavy rainstorms and synthetically describe their characteristics. The notable size of the employed sample, including data with a very detailed resolution in time, that relate to several rain gauges well-distributed throughout the region, give robustness to the obtained results.

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Lightning and rain dynamic indices as predictors for flash floods events in the Mediterranean

Advances in Geosciences ◽

10.5194/adgeo-23-57-2010 ◽

2010 ◽

Vol 23 ◽

pp. 57-64 ◽

Cited By ~ 15

Author(s):

N. Harats ◽

B. Ziv ◽

Y. Yair ◽

V. Kotroni ◽

U. Dayan

Keyword(s):

Flash Flood ◽

Heavy Precipitation ◽

Flash Floods ◽

Lightning Activity ◽

Specific Humidity ◽

Flood Events ◽

Funded Project ◽

The Mediterranean ◽

Good Concordance ◽

Short Term Forecasting

Abstract. The FLASH EU funded project aims to observe, analyze and model lightning activity in thunderstorms for use in short term forecasting of flash floods in the Mediterranean region. Two new indices, aimed to assess the potential for heavy precipitation and flash-floods, are proposed and evaluated. The first is a lightning index – the MKI, which is a modified version of the KI-index. The applied index gives more weight to the lower- and mid-level relative humidity. The second is a new rain index, the RDI, which is the integrated product of specific humidity and vertical velocity. With the aim to contribute to the aforementioned objectives, 3 flash flood events, two in Israel and one in Greece are analyzed in the present study, using the 2 proposed indices. The NCEP/NCAR reanalysis database, of 2.5°×2.5° resolution, failed to resolve the meso-scale features of the observed flash flood events. Therefore, the ECWMF database, of 0.5°×0.5° resolution, was used for calculating and displaying the two indices. Comparison between the observed rain and lightning and the respective indices for the two pieces of data was performed for the flash flood events. The results show good concordance of both indices with timing and spatial distribution in 2 of them, while in one of them is displaced by more than 50 km. The good agreement in locating the maximum between the MKI and RDI suggests that the proposed indices are good predictors for both intense lightning activity and torrential rain and consequently, for potential flash floods.

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