The catastrophic flash-flood event of 8–9 September 2002 in the Gard region, France: a first case study for the Cévennes–Vivarais Mediterranean Hydrometeorological Observatory

The Cévennes–Vivarais Mediterranean Hydrometeorological Observatory (OHM-CV) is a research initiative aimed at improving the understanding and modeling of the Mediterranean intense rain events that frequently result in devastating flash floods in southern France. A primary objective is to bring together the skills of meteorologists and hydrologists, modelers and instrumentalists, researchers and practitioners, to cope with these rather unpredictable events. In line with previously published flash-flood monographs, the present paper aims at documenting the 8–9 September 2002 catastrophic event, which resulted in 24 casualties and an economic damage evaluated at 1.2 billion euros (i.e., about 1 billion U.S. dollars) in the Gard region, France. A description of the synoptic meteorological situation is first given and shows that no particular precursor indicated the imminence of such an extreme event. Then, radar and rain gauge analyses are used to assess the magnitude of the rain event, which was particularly remarkable for its spatial extent with rain amounts greater than 200 mm in 24 h over 5500 km2. The maximum values of 600–700 mm observed locally are among the highest daily records in the region. The preliminary results of the postevent hydrological investigation show that the hydrologic response of the upstream watersheds of the Gard and Vidourle Rivers is consistent with the marked space–time structure of the rain event. It is noteworthy that peak specific discharges were very high over most of the affected areas (5–10 m3 s−1 km−2) and reached locally extraordinary values of more than 20 m3 s−1 km−2. A preliminary analysis indicates contrasting hydrological behaviors that seem to be related to geomorphological factors, notably the influence of karst in part of the region. An overview of the ongoing meteorological and hydrological research projects devoted to this case study within the OHM-CV is finally presented

Pharmacogenomics of statin-related myopathy:Meta-analysis of rare variants from whole-exome sequencing

AIMS:Statin-related myopathy (SRM), which includes rhabdomyolysis, is an uncommon but important adverse drug reaction because the number of people prescribed statins world-wide is large. Previous association studies of common genetic variants have had limited success in identifying a genetic basis for this adverse drug reaction. We conducted a multi-site whole-exome sequencing study to investigate whether rare coding variants confer an increased risk of SRM. METHODS AND RESULTS:SRM 3-5 cases (N = 505) and statin treatment-tolerant controls (N = 2047) were recruited from multiple sites in North America and Europe. SRM 3-5 was defined as symptoms consistent with muscle injury and an elevated creatine phosphokinase level >4 times upper limit of normal without another likely cause of muscle injury. Whole-exome sequencing and variant calling was coordinated from two analysis centres, and results of single-variant and gene-based burden tests were meta-analysed. No genome-wide significant associations were identified. Given the large number of cases, we had 80% power to identify a variant with minor allele frequency of 0.01 that increases the risk of SRM 6-fold at genome-wide significance. CONCLUSIONS:In this large whole-exome sequencing study of severe statin-related muscle injury conducted to date, we did not find evidence that rare coding variants are responsible for this adverse drug reaction. Larger sample sizes would be required to identify rare variants with small effects, but it is unclear whether such findings would be clinically actionable

Mise en évidence de loci chromosomiques de susceptibilité pour le lupus érythémateux systémique

LILLE2-BU Santé-Recherche (593502101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

L’établissement de hauteur du Malpas à Soyons (Ardèche) durant l’Antiquité tardive (IVe – VIe s.)

Investigations have started again on the hillfort of Malpas at Soyons (Ardèche) in February 2013. Two trenches have revealed four different occupation stages corresponding to Late Bronze Age, Late Hallstatt, La Tene D and Late Antiquity. Middle-aged occupations can’t be observed by stratigraphy. Studies of artefacts have revealed two different occupation stages for Late Antiquity. The first one is characterized by a backfill layer dated from the first half of 5th century, and the second one by the filling of hollow structures dated from the first half of 6th century. Compared to the former discoveries, these well preserved remains provide some stimulating researches that we present here.La reprise des recherches sur le site de hauteur du Malpas à Soyons (Ardèche) en février 2013 a permis d’observer, grâce à deux sondages, quatre grandes phases d’occupations correspondant au Bronze Final, au Hallstatt final, à La Tène D et à l’Antiquité tardive. Les occupations médiévales, n’ont pas pu être observées en stratigraphie. L’étude détaillée des vestiges et du mobilier correspondant à cette ultime phase antique révèle au moins deux états d’occupation, un premier caractérisé par un remblai daté de la première moitié du Ve s. et un second par les comblements de structures en creux datées de la première moitié du VIe s. Confrontés aux découvertes anciennes, ces vestiges bien conservés offrent de stimulantes perspectives de recherche que nous exposons ici

L’établissement de hauteur du Malpas à Soyons (Ardèche) durant l’Antiquité tardive (IVe – VIe s.)

Investigations have started again on the hillfort of Malpas at Soyons (Ardèche) in February 2013. Two trenches have revealed four different occupation stages corresponding to Late Bronze Age, Late Hallstatt, La Tene D and Late Antiquity. Middle-aged occupations can’t be observed by stratigraphy. Studies of artefacts have revealed two different occupation stages for Late Antiquity. The first one is characterized by a backfill layer dated from the first half of 5th century, and the second one by the filling of hollow structures dated from the first half of 6th century. Compared to the former discoveries, these well preserved remains provide some stimulating researches that we present here.La reprise des recherches sur le site de hauteur du Malpas à Soyons (Ardèche) en février 2013 a permis d’observer, grâce à deux sondages, quatre grandes phases d’occupations correspondant au Bronze Final, au Hallstatt final, à La Tène D et à l’Antiquité tardive. Les occupations médiévales, n’ont pas pu être observées en stratigraphie. L’étude détaillée des vestiges et du mobilier correspondant à cette ultime phase antique révèle au moins deux états d’occupation, un premier caractérisé par un remblai daté de la première moitié du Ve s. et un second par les comblements de structures en creux datées de la première moitié du VIe s. Confrontés aux découvertes anciennes, ces vestiges bien conservés offrent de stimulantes perspectives de recherche que nous exposons ici

Results of the post-event survey conducted after the extreme flash flood occurred in the Var region (South of France) in June 2010

The opportunities to study and understand flash floods still remain highly limited by the lack of observations. If not destroyed or damaged during the flood events, the existing river gauging station networks are too sparse to capture in detail the spatio-temporal pattern of these floods, generally affecting small rivers. Moreover the short duration of flash floods (few hours) limits the possibility for conducting real time field observations. In this context,extensive post-event surveys can be of great interest to collect information that can be useful to better understand the phenomena, and to define mitigation measures that may reduce damages in the future: spatio-temporal pattern of the flood, flows based on discharge estimations and interviews of witnesses, delineation of the flooded areas based on high-water marks, detail and causes of damages, circumstances of deaths...The present communication presents the outcomes of the post-event survey conducted after the extreme flash floods that occurred on the 15th and 16th of June 2010 around the town of Draguignan, in the South of France. The floods were induced by an extraordinary rainfall event: rainfall accumulations exceeding 400mm within 24-hours were recorded. It is by far the record daily accumulation for the region according to the data ofthe existing raingauge network, its estimated return period exceeding largely 100-years. The induced flash floods caused important damages to several towns and 25 casualties. Technical services of the French State and local authorities as well as research institutions involved in the HYMEX project collaborated to the extensive field survey conducted after the floods. The collected data set includes discharge estimates at the gauged stations by water level reconstitution and rating curve extrapolation(half of the hydrological network crashed down during the event), more than 35 peak discharge estimates at various ungauged locations of the stream network, with often an idea of the time of the peak obtained through witnesses' interviews, and more than 1200 geo-referenced high water marks. This data set provides interesting information about the spatial variability of the hydrological response of the watersheds and about the dynamics of propagation of the flood. Based on this data set, it was possible to reconstitute the flood genesis and also to estimate the possible return periods of the estimated peak discharge values along the river network. The circumstances of the casualties were also analysed, in order to understand how they could have been avoided. Some recommendations - already partly put into action - were formulated to reduce in the future the impact of such an event, such as the strengthening of the gauging network, the development of a flood warning system based on the experience gained through the post event survey, or the application of more constraining building regulations in the exposed areas. The affected area (South Eastern part of France where no extraordinary flash flood had been so deeply documented in the past) and the collaboration between technical services and a large number of research institutions during a post-event survey make of this survey a particularly interesting case study

A Radar Simulator for High-Resolution Nonhydrostatic Models

International audienceA full radar simulator for high-resolution (1–5 km) nonhydrostatic models has been developed within the research nonhydrostatic mesoscale atmospheric (Meso-NH) model. This simulator is made up of building blocks, each of which describes a particular physical process (scattering, beam bending, etc.). For each of these blocks, several formulations have been implemented. For instance, the radar simulator offers the possibility to choose among Rayleigh, Rayleigh–Gans, Mie, or T-matrix scattering methods, and beam bending can be derived from an effective earth radius or can depend on the vertical gradient of the refractive index of air. Moreover, the radar simulator is fully consistent with the microphysical parameterizations used by the atmospheric numerical model. Sensitivity experiments were carried out using different configurations for the simulator. They permitted the specification of an observation operator for assimilation of radar reflectivities by high-resolution nonhydrostatic numerical weather prediction systems, as well as for their validation. A study of the flash flood of 8–9 September 2002 in southeastern France, which was well documented with volumetric data from an S-band radar, serves to illustrate the capabilities of the radar simulator as a validation tool for a mesoscale model

A radar observation operator for high resolution non hydrostatic numerical weather prevision.

In order to specify an observation operator for radar reflectivities for the next numerical weather prediction model of Météo-France, a radar simulator was implemented in the research model Meso-NH. This tool was made up of building blocks that each describe a particular physical process (scattering, beam bending, etc.). Sensitivity experiments were carried out using different configurations for the modules. They allowed to specify an observation operator as a compromise between accuracy and computing constraints

Inter-disciplinary post-event surveys to untangle hazard and vulnerability in the impacts of flash-flood events in the Mediterranean.

Heavy precipitation events (HPE) and flash floods (FF) are common phenomena over the Mediterranean region. The peculiar topography and geographical location of this area make it especially favorable to the occurrence of intense events. The Mediterranean Sea acts as a vast heat andmoisture reservoir from which baroclinic atmospheric systems pump part of their energy. The steep orography surrounding the Mediterranean Sea favors lifting of the low-level unstable air and initiation of condensation processes. Although they occur in well-known synoptic conditions, these intense rainfall events result from complex interactions between the atmosphere, the sea and continental surfaces. Mesoscale processes (orographic forcing, but also deflection and convergence of air masses, formation of cold pools and down-valley flows, etc.) lead to a variety of convective systems ranging from orographic rainfall events, thunderstorms to the most dangerous stationary mesoscale convective systems (MCS) (Bresson et al. 2012). Despite recent progress due to the assimilation of mesoscale meteorological data in highly resolved numerical weather prediction models, the predictability of thunderstorms and MCSs remains quite low both in terms of intensity and localization