A spectacular landslide in the Maurienne valley (Savoie) following a heat wave followed by heavy rains shut down rail and heavy goods traffic on a major axis between France and northern Italy.
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The return to normal could take several days, according to authorities, and the sector remained under surveillance pending the eviction on Monday.
On Sunday around 5.15 p.m., “several boulders with a volume of about 700 m3” hit the protective grid installed on the RD 1006 in a “particularly monitored sector” in the town of Saint-André in La Praz, explains the Savoie Prefecture in a press release.
The landslide occurred during an “episode of rain with significant runoff, which followed a heat wave across the Alps,” explained Denis Roy, head of Météo France’s Northern Alps mountain centre.
In images circulated on social networks, we can see how a large cloud of dust falls from a cliff and falls onto the departmental road next to the railway line and the A43 motorway below.
Fortunately, RD 1006 was closed half an hour before the landslide after a “unit block fall,” said AFP Jean-Philippe Laplanche, infrastructure department director. The department is on Yellow Alert Storm Warning and we are “very vigilant to these types of events” that may affect infrastructure, he said, stressing that these phenomena “are gaining momentum with climate change.”
The SNCF announced that train services on the Chambéry-Turin route were interrupted, as was that of the TER in the Maurienne valley.
“It’s closed at least up to and including Wednesday,” but we “expect it will be longer,” SNCF told AFP. Trenitalia also announced the suspension of its services between Modane and Paris up to and including Wednesday.
“Access to the site is still banned by the prefecture due to the continued risk of landslides. As soon as we have access to it, we can make a diagnosis by geologists from the prefecture and the DDE to check the risks and then “check the damage”, added the SNCF, then specifying that a helicopter overflight of the area will be necessary had to be canceled due to the weather.
Weather favors landslides
In addition to the departmental road being closed to all traffic between the RD 1006/RD 215 junction and the Freney interchange, the A43 has also been closed in both directions between junctions 29 and 30 indefinitely, “the time to clear the debris remove”. dumped on the highway after this landslide,” the prefecture said.
A detour has been set up for light vehicles. The Fréjus cross-border road tunnel has been closed to vehicles over 3.5 tons, heavy trucks and coaches have been asked to “pass through the Mont Blanc tunnel or the A8 motorway,” the prefecture notes.
The French concession company Autoroutes et Tunnel du Mont-Blanc (ATMB) recorded there at midday a waiting time of 2h15 at the tollbooth on the French side and 3h00 on the Italian side.
“This succession of hot weather followed by heavy rains” could have caused the instability of the rock, explains Serge Taboulot, President of the Institute for Major Risks in Grenoble, recalling the series of landslides that have occurred in the high mountains in recent days have.
“The mountain has always collapsed, but there are times that are more favorable than others, such as this somewhat unusual heatwave,” he added.
After ten days marked by an exceptional heat wave, Savoie, as well as Haute-Savoie and Isère, have issued a yellow rain and flood warning. Up to 40 mm of rain is expected in the entire area of the landslide on Monday and “at this point the risk still exists,” the prefecture told AFP at noon.
On July 2, 2019, a torrential lava flow of 1,000 m3 undermined the rails at Saint-Michel de Maurienne for 60 meters, causing a three-week suspension of rail traffic between France and Italy via Modane.