Flash flood swept across southern France on Thursday, August 9, 2018. An intense storm system dumped over 100 mm of rain in 1 hour in the Rhône Valley, France, causing rivers to overflow the banks. The storms which caused the floods came after a period of unusually hot weather in southern France and much of Europe. According to Meteo France, by 5 pm on August 9, 240 mm of rain had fallen in Saint-Martin-d’Ardèche, with 105 mm of that total falling in just 1 hour. Vallon-Pont-d’Arc, also in Ardèche, 201 mm of rain recorded during the same period. In Gard department, Méjannes-le-Clap recorded 167 mm of rain and Bessèges, situated on the Cèze River, a tributary of the Rhône, recorded 150 mm.
Recorded Rainfall Distribution Map in August 9, 2018
(Credit: Meteo France)
France’s Ministry of Interior said the storm caused a sudden flash flood of tributaries of the Rhône and Ardèche Rivers. Ardèche, Gard and Drôme departments were all affected. In a statement of August 9, the Ministry said that a team of 400 Gendarmerie, firefighters, police and civil security, as well as 4 helicopters, were mobilized and sent to the flood affected areas.
Flooding in Gard department in August 9, 2018
(Credit: Pompiers du Gard)
According to the Ministry of Interior, the heavy rainfalls in the northern part of the Gard department turned the Cèze and Ardèche Rivers into churning waterways that quickly spilled out of their banks. Below is a figure showing the cumulative rainfall (mm, every 6 hours), river flow discharges (m3/s, every 5 minutes) and river heights (m, every 5 minutes) for August 9 Flood recorded at Hydrologic Station Tharaux (V5454010), located on the lower Cèze River. The measured peak flood height at this location is 5.73 meters of this event.
Cumulative Rainfall (mm), Flow Discharges (m3/s) and River Heights (m) for August 9 Flood at Tharaux Station on the Lower Cèze River
(Credit: Vigicrues, information service on the flood risk of major rivers in France)
As many as 1,600 people were evacuated in the area, most of them campers. Some houses on the banks of the Cèze River in Goudargues were also evacuated. The evacuated campers included 119 children from Germany in Saint-Julien-de-Peyrolas, Gard department, where the Ardèche River burst its banks. A 70-year-old German man who was helping to supervise children at one of the summer camps was reported missing during the flood. At least 160,000 lightning strikes were recorded by midday on Thursday. About 17,000 homes were without power in the south-west and north-east of France. Numerous roads in the area remained cut off as night fell.
Rescuers in a Flooded Area of a Camping Site after Heavy Rain and Flash Flood Swept
(Credit: BORIS HORVAT / AFP / Getty Images)
