All posts by Jérémie Voumard

Bad weather in Graubünden, July 2015

Two severe storms at one day interval have caused damages due to debris flow in Scuol (GR), lower Engadine, at the end of July .

During two days of high precipitations in Scuol, on 22 and 23 July 2015, several debris flow caused many infrastructures damages.

On 22 July 2015, three buildings in the Pradella hamlet near Scuol were damaged by a debris flow. People of two holiday camps, 100 children and 40 adults, were evacuated. Nobody was injured but the buildings damages are important.

A day after, about 200 mm rain in a short time were measured in the same area. An auto has been swept away by a debris flow in the Scuol village and its driver could escape at the last moment.

The S-Charl valley was isolated during more than one week by seven big debris flows and several little ones. About 100 people, in majority holidaymakers, were blocked in the S-Charl hamlet without power supply during few days. Until the swiss army built a provisional emergency bridge to open the valley access, the only way to access the S-Charl valley was by helicopter.

Overall damages –roads infrastructures, buildings, drinking water supply, power supply and other- are estimated to one million Swiss Francs and the debris flow volume is estimated to 100’00 cubic meters.

Sources: NZZ (1, 2, 3 and 4)

Images sources: J. Voumard – Risk Group

Military bridge and debris flow in S-Charl valley

Lake generated by debris flow in S-Charf valley

Debris flow in Scuol

Damaged house in Pradela hamlet

Bad weather in Western Switzerland, May 2015

Bad weather caused damages and evacuations in Western Switzerland in early May due to floods, debris flow and landlsides.

Strong precipitations occurred on Western Switzerland in the beginning of May 2015, especially on May 1st. Over 100 mm of rain fell in about 24 hours in some places in Western Switzerland, with a maximum of 130 mm at La Dôle, Canton of Vaud. Those heavy rains caused different damages as debris flow, floods and landslides.

Several roads and railway have been closed, preventively or due to tracks obstructions in the Alps, the Jura mountains and in the Swiss Plateau. Two landslides have disrupted two main railway tracks, causing high traffic disturbances due to deviations and affecting the railway traffic during more than one week.

In the village of St-Gingolph in the Canton of Valais, the Morge river -which is the border between Switzerland and France along the lake Léman- overflowed two restaurants with debris flows. Their groundfloor levels have been totally destroyed.

In the town of Monthey, Canton of Valais, about 300 residents along the Viège river have been evacuated during the night because of the high risk of floods.

The Arve river -which flows through the Chamonix Valley in the French Alps- has reached a flow rate record with 903 m3/s compared to its standard flow of 77 m3/s at its mouth into the Rhône river in Geneva on 2nd May. Several bridges in the town had to be closed, affecting the urban traffic of the second biggest town of Switzerland.

North-east of the Western Switzerland, the lakes of Neuchâtel (Canton of Neuchâtel), Biel (Canton of Bern) and Morat (Canton of Fribourg), overflowed because of the high flow rate of the Aare river. The maximum height of water level has been reached about 8 days after the first heavy rain with a water level increase of 1 meter. A lot of wood has been carried by the rivers to the shores of the lakes.

The damages are only material, no injuries were identified. Financial and temporal damages consequences are high for the two destroyed restaurants. The return to normality for river flows and water levels of the lakes took several weeks.

Sources: Federal Office for the Environment, Tribune de Genève, Le Temps

Images sources: J. Voumard – Risk Group

Grande_Eau_River Wood_on_Lake_Leman St-Gingolph_Restaurants St-Gingolph Restaurant_in_St-Gingolph Morge_River_in_St-Gingoph Media_in_Lutry Landslide_Flamatt Lake-of-Neuchatel Island_Lake-of-Neuchatel

Publication of a report on a hail event

The swiss Intercantonal Reinsurance (VKF/UIR) published a report on a hail event which occurred in Northern Switzerland in 2011. This report has been written in collaboration with our group. The study focuses on the Canton of Aargau, which was particularly affected by the event, and takes advantage of insurance data and hail intensity derived from meteorological radars.

The document is available online in french or in german.


Risk group @ EGU 2015 in Vienna

23 persons of the Risk Group participated to the European Geosciences Union (EGU) General Assembly in Vienna, Austria, on 13 April to 17 May 2014. This huge meeting brought together 11’837 scientists from 108 countries. It is always an excellent opportunity for our group to meet new people and other scientists we work with for a long time during the five days of the meeting.

The Risk Group presented 30 contributions which are bellow by alphabetical order given.

Dario presenting his PICO

Pierrick presenting his talk

Liliane presenting her poster

Presentations: 11 presentations, whose 6 orals, 4 PICO and one short course

  • Can we use ice calving on glacier fronts as a proxy for rock slope failures? Antonio Abellan et al.
  • New insights into 3D calving investigations: use of Terrestrial LiDAR for monitoring the Perito Moreno glacier front (Southern Patagonian Ice Fields, Argentina) Antonio Abellan et al.
  • Short course: Use of 3D point clouds in Geosciences: Acquisition, Processing and Applications Antonio Abellan, Dario Carrea, Florian Humair, Antoine Guerin, Marc-Henri Derron, and Michel Jaboyedoff
  • A prototype of an interactive web-based risk analysis tool for floods and landslides Zar Chi Aye et al.
  • Current challenges for high-resolution monitoring of deep geological repository boreholes using terrestrial laser scanner and photogrammetry Dario Carrea et al.
  • Transition between folding and thrusting: numerical simulations and applications to the Swiss Jura Mountains and the Canadian Foothills Florian Humair et al.
  • Understanding surface processes 3D imaging from micro-scale to regional scale Michel Jaboyedoff et al.
  • A LiDAR intensity correction model for vertical geological mapping Dario Carrea et al.
  • Characterization of the Jure (Sindhupalchok, Nepal) Landslide by TLS and field investigations Michel Jaboyedoff et al.
  • Conceptual issues with risk analysis in Switzerland Pierrick Nicolet et al.
  • Sediment cascade modelling for stochastic torrential sediment transfers forecasting in a changing alpine climate Benjamin Rudaz et al.

Posters: 19 posters whose 4 of Master students

  • Landslide mapping and analysis of Korbous area, Cap Bon (Northern Tunisia) Mariam Ben Hammouda et al.
  • Analysis of a high-alpine steep rockfall – the case of the southeastern face of the Piz Lischana (Grisons, Switzerland) Susanna Büsing et al.
  • DInSAR fringes simulation of sandbox models Marc-Henri Derron et al.
  • Modelling landslide-generated tsunami: from landslide propagation to downstream flood in dam context Martin Franz et al.
  • Thermal monitoring of a granitic exfoliation sheet and cliff in Yosemite Valley, California (USA) Antoine Guerin et al.
  • Parametric study of the impact of waste pollutants on groundwater: the case of Abidjan District (Ivory Coast) Amenan Agnès Kouamé et al.
  • Unplanned roads impacts assessment in Phewa Lake watershed, Western region, Nepal Geoffroy Leibundgut et al.
  • Fracture analysis of an Eocene reservoir in Eastern Tunisia by coupling Terrestrial Laser Scanning with GigaPan Technology and seismic attribute Raja Mastouri et al.
  • Assessing hail risk for a building portfolio by generating stochastic events Pierrick Nicolet et al.
  • 3D mapping of geological contacts by coupling Aerial Laser Scanning, Gigapixel photography and open access pictures Liliane Nguyen et al.
  • Identification of synoptic precursors to extreme precipitation events in the Swiss Alps by the analysis of backward trajectories Liliane Nguyen et al.
  • Multi Criteria Evaluation Module for RiskChanges Spatial Decision Support System Roya Olyazadeh et al.
  • Analysis of a creeping marls event in the coastal cliffs of Bessin, Basse-Normandie, France Alizée Vioget et al.
  • Application on-line imagery for photogrammetry comparison of natural hazards events Jérémie Voumard et al.
  • Impacts of the November 2014 extreme rainfall event in Ticino, Switzerland Jérémie Voumard et al.
  • Application of WebGIS for traffic risk assessment Jérémie Voumard et al.
  • Characterization of sediment sources, sediment budget estimations, consequences and implications for populations in the Jatún Mayu watershed (Cochabamba, Bolivia) Jean-Marie Vuignier et al.
  • Contribution of terrestrial and helicopter based laser scanning for studying the Sechilienne rock slope instability (Isère, France) Cindy Vulliez et al.
  • Experimental quantification of a granular crater induced by a liquid-to-granular impact using a 3D scanner Emmanuel Wyser et al.


Mudslide crashed into a small building in the Swiss Alps

A three-storey appartment building was destroyed by a landslide on November 16th 2014 in the canton of Ticino, Switzerland. Two women were killed.

At 2:30 pm, a wall -weakened by the heavy rainfalls- located 50m away and above the building broke, releasing 500 m3 to 1’000 m3 of muddy material in the Davesco-Soragno village, near of Lugano. Hundred rescuers accompagnied by sniffer dogs worked during the night in the rubble to find the victims. Besides two fatalities, one man was seriously injured, three persons were slightly injured and one person kept uninjured.

Strong rain precipitations occurred since at least ten days before the event on the area of Lugano. This landslide occurred 11km away from the previous disaster where two persons were killed 11 days ago.

Sources: bbc, rts, 24heures and 20minuten.

Davesco-Soragno - Keystone/Gabriele Putzu Keystone/Gabriele Putzu

Davesco-Soragno 2 - Keystone/Gabriele Putzu Keystone/Gabriele Putzu

Davesco-Soragno 3 - Keystone/Gabriele Putzu Keystone/Gabriele Putzu

Davesco-Soragno, event location / Copyright: swisstopo Copyrights Swisstopo


Landslide destroy a house in Swiss Alps

A two-storey house located in a large wooded area was destroyed by a landslide on November 5th 2014 in the canton of Ticino. The two occupants, a mother and her three years old daughter, were killed.

Shortly after 6:00 pm, a 1’000 m3 landslide composed of mud, trees and rock masses flew over 150 meters and hit a house of the Bombinasco village, 10km West of Lugano. Eighty people (rescuers, firefighters and sniffer dogs) worked all the night in the rubble and found the two victims at 4:30 am the following day.

Strong rain precipitations occurred before and during the event on the area of Lugano. A road close to the drama location was buried by a landslide few hours before.

Sources: 24heures, 20minutes and blick.

 Rescue Media Rescue Media

Keystone/Gabriele Putzu Keystone/Gabriele Putzu

Event location / Copyright Swisstopo Copyrights Swisstopo


Train derailed due to a landslide in Swiss Alps

A train of the Rhaetian Railway derailed into a ravine after hitting a landslide felt on the track on August 13th 2014. Eleven persons were injured, five of them seriously. One person died in the hospital ten days after the event. About two hundred persons were in the train.

Almost 180 rescuers with eight ambulances and four helicopters were involved in the rescue operations. The landslide occurred near the village of Tiefencastel between Chur and St-Moritz in the canton of Grisons. A 15 m long section of the railway track was buried with up to 3 m of material.

When the train hit the landslide, three passenger cars derailed. The first one, placed behind the locomotive, felt down about twenty meters into a ravine with a 45° slope. It was stopped during its fall by trees. The second passenger car stayed on equilibrium over the edge with the help of passengers who went to the back of the car to avoid its fall.

Weather conditions seem to have contributed to this event. It rained between 50 and 60 liter per square meter in 12 hours. This represents half of the usual monthly rain precipitations in the area.

Sources: bbc, 24heures, 20minutes.

Keystone Keystone

AFP Michael Buholzer AFP / Michael Buholzer


(c) Swisstopo Copyright Swisstopo


Napoleome project

The Napoleome project of the University of Lausanne is a participatory scientific project about genomics. Public conferences and workshops are organized to popularize the research and issues in genetics.

Practically, the project shows that genetic diversity can take place inside a single individual, by decoding the full genome of the Napoléon oak tree located on the University campus. Because of its experience in terrestrial LiDAR, the Risk Group (mainly by J. Voumard, S. and Hiscox (FGSE) supported by C. Longchamp, M.-H. Derron & M. Jaboyedoff) has been asked to scan this 200 years old tree in 3D. Eight LiDAR scans were made around the tree and then merged to get the whole tree structure as a 3D point cloud. These data have then be used by web designers to produce a 3d meshed model.

Further information about the project, collaborators, activities … are avaliable on the Napoleome project website (in french).

Oak tree, Napoleome

Napoleome website printsreen

Group excursion in the Jura

Early July, the Risk Group went out for an entertaining afternoon. The excursion started with the Vallorbe Caves , in the Jura Mountains. Those caves result of limestone erosion by the underground Orbe River. A 3km long path passes through various galleries and rooms, with numerous concretions and underground lakes. The visit finished with a tasting of cheese ripened in the Vallorbe Caves. The whole group then joined the Chalet du Suchet restaurant, on the Jura crest, for a dinner around a delicious cheese fondue.

Group excursion, Caves at Vallorbe

Group excursion, Caves at Vallorbe 2

Group excursion, Suchet view

Group excursion, dinner