Europe 1 with AFP / Photo credit: AFP PHOTO / GENDARMERIE NATIONALE / BACHELOT 14:18 pm, August 28, 2023

A spectacular rockslide in the Maurienne valley in Savoie after a heat wave followed by heavy rains led to a suspension of rail traffic and heavy goods vehicles on a major axis between France and northern Italy. It could take several days to return to normal.

A spectacular rockslide in the Maurienne valley in Savoie after a heat wave followed by heavy rains led to a suspension of rail traffic and heavy goods vehicles on a major axis between France and northern Italy. The return to normal could take several days, and the area remained under surveillance Monday pending clearing. Sunday, around 17:15 p.m., "several blocks of rocks representing a volume of about 700 m3" hit the protective screen installed on the RD 1006, in a "particularly monitored sector" in the town of Saint-André, in La Praz, explained the prefecture of Savoie in a statement.

Big landslide in the late afternoon in Saint-André in Savoie. The A43 motorway is closed and train traffic between France and Italy is suspended until further notice. (Loïc Borella) pic.twitter.com/8oy4OSOvJI

— Anonymous Citizen (@AnonymeCitoyen) August 27, 2023

The landslide occurred during a "rainy episode, with significant runoff, which followed a heat wave in all the Alps," said Denis Roy, head of the Northern Alps mountain center of Météo France. On images posted on social networks, we can see a large plume of dust toppling from a cliff and falling on the departmental road adjoining the railway and the A43 motorway below.

Bus alternatives

Fortunately, the RD 1006 had been closed half an hour before the landslide after a "fall of unitary block", told AFP Jean-Philippe Laplanche, departmental director of infrastructure. The department was on thunderstorm alert and we are "very vigilant on this type of event" that can affect infrastructure, he said, stressing that these phenomena "accelerate with climate change". On Monday morning, the road remained covered by scree, an AFP journalist found.

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Train traffic on the Chambéry-Turin line has been interrupted, as has that of the TER in the Maurienne valley with alternative solutions by bus, said SNCF. Trenitalia also announced the cancellation of its routes between Modane and Paris until Wednesday included. "It is closed at least until Wednesday included" but it is "expected to last longer," SNCF told AFP. "The site is still closed to access by the prefecture, because there is still a risk of landslides. As soon as we can access it, we will be able to establish a diagnosis" of the geologists of the prefecture and the DDE, to check the risks" and then "check the damage", added the SNCF.

A diversion for light vehicles

In addition to the departmental road, closed to all traffic between the RD 1006 / RD 215 intersection and the Freney interchange, the A43 was also closed between ramps 29 and 30 in both directions for an indefinite period, "the time to clear the debris that settled on the highway following this landslide" according to the prefecture. A diversion has been set up for light vehicles. The cross-border road tunnel of Fréjus has been closed for vehicles over 3.5 tons, heavy goods vehicles and coaches have been invited to "transit through the Mont Blanc tunnel or the A8 motorway", notes the prefecture.

The French concession company Autoroutes et Tunnel du Mont-Blanc (ATMB) reported at midday 2h15 of waiting at the toll booth on the French side and 3h on the Italian side. "This succession of hot followed by heavy rains" may have caused the instability of the rock, says Serge Taboulot, president of the Institute of Major Risks in Grenoble, recalling the series of landslides that have occurred in recent days in the high mountains. "The mountain has always collapsed but there are periods more propitious than others, such as this heat wave a little out of the ordinary," he added.

After ten days marked by an exceptional heat wave, the snow whitens several summits in the Hautes-Alpes while Savoie is, like Haute-Savoie and Isère, on yellow alert rain-floods. Up to 40mm of precipitation is expected cumulatively Monday on the landslide sector and "at this time, the risk is still present," the prefecture told AFP at midday.