This article analyzes recent trends in extreme precipitation the Southwestern Alps and compares these to changes occurrence of atmospheric influences generating extremes. We consider a high-resolution dataset 1 × km 2 for period 1958–2017. A robust method trend estimation is considered, based on nonstationary value distribution homogeneous neighborhood approach. The results show contrasting depending season. In autumn, most Southern France shows significant increasing trends, with increase...

On June 21st, 2024, the iconic village of La Bérarde, in centre massif Les Ecrins, French Alps, was destroyed by mountain stream “Les Etancons”, that flooded houses  and deposited more than 200,000 m3 raw material. This catastrophic event caused concomitance rapid warming with a heavy rain on top snowpack unusually thick glaciated watershed ranging from 1700 m to 4000 a.s.l. during which glacial lake drained simultaneously. Using observations (in-situ...

Abstract This article analyzes the large-scale circulations producing daily precipitation extremes in Southwestern Alps and their trends from 1958 to 2017. We consider a high-resolution data set of 1 × km 2 weather patterns associated seasonal maxima at each grid point. The allows us analyze details atmospheric influences triggering maxima. Four are considered—the Atlantic influence, Mediterranean northeast circulation Anticyclonic situation. show that on very well organized space but...

Abstract Extreme precipitation in the Northern French Alps are mainly associated with large‐scale circulations (LSCs) bringing moist air from Atlantic Ocean and Mediterranean Sea—two atmospheric influences that very frequent climatology. In this work, we investigate what characterizes Atlantic/Mediterranean driving extreme comparison to ‘random’ circulations. We focus on 3‐day over two medium size neighbouring catchments 1950 2017. identified using an existing weather pattern classification...

Abstract This work analyses the link between Western Europe large‐scale circulation and precipitation variability in Northern French Alps from 1950 to 2017. We consider simple descriptors characterizing daily 500 hPa geopotential height fields. They are maximum pressure difference (MPD)—representing range of heights over Europe, singularity—representing mean distance a shape its closest analogs, that is, way this is reproduced climatology. show MPD singularity shapes explain significant part...

Abstract. Detecting trends in regional large-scale circulation (LSC) is an important challenge as LSC a key driver of local weather conditions. In this work, we investigate the past evolution western Europe based on 500 hPa geopotential height fields from 20CRv2c (1851–2010), ERA20C (1900–2010) and ERA5 (1950–2010) reanalyses. We focus characteristics using three atmospheric descriptors that are analogy by comparing daily to each other. They characterize stationarity shape how well...

Abstract. Detecting trends in regional large-scale circulation (LSC) is an important challenge as LSC a key driver of local weather conditions. In this work, we investigate the past evolution Western Europe based on 500 hPa geopotential height fields from 20CRv2c (1851–2010), ERA20C (1900–2010) and ERA5 (1950–2010) reanalyses. We focus characteristics using three atmospheric descriptors that are analogy – characterizing shape stationarity how well reproduced climatology together with...

Abstract Detecting trends in regional large‐scale circulation (LSC) is an important challenge as LSC a key driver of local weather conditions. In this work, we focus on two characteristics that are linked to the generation extreme precipitation northern French Alps and allow interpreting changes flow direction intensity. Considering 500 hPa geopotential height fields, show CNRM‐CM6‐1 climate model simulates future circulations (2015–2100) will tend feature stronger flows with more marked...

<p>We analyze recent trends in extreme daily precipitation the Southwestern Alps. We consider a high-resolution dataset of 1 x1 km<sup>2</sup> for period 1958-2017. A robust method trend estimation is considered, based on nonstationary value distribution and homogeneous neighborhood approach. The results show contrasting depending season. In autumn, are significantly increasing most Greater Alpine Region, with an increase up to 100% average maxima...

<p>Extreme precipitation in the Northern French Alps are mainly associated with large-scale circulations (LSCs) bringing moist air from Atlantic Ocean and Mediterranean Sea - two atmospheric influences that very frequent climatology. In this work, we investigate what characterizes Atlantic/Mediterranean driving extreme comparison to "random" circulations. We focus on 3-day over medium size neighboring catchments 1950 2017. identified using an existing weather...

Abstract. In this article we study the atmospheric conditions at origin of damaging torrential events in Northern French Alps over long run, using a database reported occurrence flooding Grenoble conurbation since 1851. We consider seven variables that describe nature air masses involved and possible triggers precipitation. Using both 20CRv2c ERA5 reanalyses, try to isolate associated with events, by objectively determining which them differ particularly from climatology dates events. This...

Abstract. The Alpine region is strongly affected by torrential floods, sometimes leading to severe negative impacts on society, economy, and the environment. Understanding such natural hazards their drivers essential mitigate related risks. In this article we propose a statistical method based mere discriminative index objectively isolate atmospheric variables associated with events long return periods. applied Grenoble Metropolitan area in Northern French Alps using list of dates damaging...

<p><span>Large-scale circulations (LSCs) explain a significant part of Alpine precipitations. Characterizing triggering heavy precipitation is usually done using weather-type classifications. A different characterization implemented here, based on analogy the atmospheric descriptors proposed in Blanchet et al 2018, 2019. These are both related to dynamics LSC and their relative position space. </span><span>This work applied...

<p>Detecting trends in regional large-scale circulation (LSC) is an important challenge as LSC a key driver of local weather conditions. In this work, we investigate the past evolution Western Europe based on 500 hPa geopotential height fields from 20CRv2c (1851-2010), ERA20C (1900-2010) and ERA5 (1950-2010) reanalyses. We focus characteristics using three atmospheric descriptors that are analogy, by comparing daily to each other. They characterize stationarity shape how well...

<p>Detecting trends in regional large-scale circulation (LSC) is an important challenge as LSC a key driver of local weather conditions. In this work, we study whether future geopotential height fields projected by climate models will change shape compared to past fields. We consider the singularity based on analogy, which defined, for given day, average distance 5\% closest shapes reference database. CNRM-CM6-1 model used circulations over 2015-2100 and, reference, analogy...

<p>This work analyses the link between Western Europe large-scale circulation and precipitation variability in Northern French Alps from 1950 to 2017. We consider simple descriptors characterizing daily 500hPa geopotential height fields. They are Maximum Pressure Difference - representing range of heights over -, singularity mean distance a shape its closest analogs, i.e. way this is reproduced climatology. These compared occurrence different atmospheric influences Atlantic,...