217 reported in 2 months: record of landslides in Quebec

Photo Sylvain Denis, QMI Agency
A portion of the rue Queen, Rawdon, in the Lanaudière region, had collapsed in April.

Nicolas Lachance

Tuesday, 1 August 2017 00:00

UPDATE
Tuesday, 1 August 2017 00:00

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There has been more soil movement in Quebec from April to June than in the previous year, a record number, since the Saguenay flood, which is of concern to the specialists.

The ministry of public Security (MSP) and the ministry of Transportation (MTQ) are overwhelmed because of the many landslides caused by the record rains of the spring.

In 2013, The Newspaper revealed that approximately 80 % of the inhabited territory of Quebec was at risk of landslides because of the sensitive clay that shape the territories of the province.

“It is not necessary to be frightened, but we must be careful,” said the Newspaper, the professor of civil engineering, Serge Leroueil, specialist in mechanics of soils and clays.

Since the beginning of the year 2017, these landslides are abundant, so that the number of cases has already doubled compared to previous years, and this, in just three months.

“Between April 1 and June 1, 2017, 217 requests for technical advice were processed by the experts in geotechnical engineering from the MTQ for the case of soil movement. It is important to note that this data is subject to change, in particular, because the year is not over, ” said the spokesperson for the MSP, Olivier Cantin.

A person has been injured in a slip of ground, reports the MSP. No death has been listed. However, the danger is alive and well, and dramas are already occurring in Quebec. May 10, 2010, in Saint-Jude, a complete family had been decimated when a mass of dirt had invaded their basement.

Record rainfall

The large rainfall would be the main cause of the propagation of landslides.

“What is remarkable, this spring, it is that there has been a strong exceedances of these averages in a very large number of regions,” says the public Safety.

The 15 meteorological stations of Quebec show that the rainfall has been well above the averages observed from 1981 to 2010.

The amounts of water received were even more monstrous in the regions of the west and centre of the province, where the average is two and a half times higher than usual.

Health concerns

Public health experts are concerned about them too, especially because of its impact on the health of the population. “It follows that because the people losing their homes. The villages and the hospitals are isolated, for example, when a road collapses.

“Then, it is clear that there is an additional risk, especially when there is no bypass road. Here, we think of all of the North Shore and the Gaspé, ” said the expert, Peter Gosselin of the Institute of public health of Quebec.

Our houses built on sensitive soils

Huge landslides ripping off abundant acres can occur at any time in Quebec, because of the large amount of clay “sensitive” in our homes that can turn into a viscous substance.

Where y a-t-he of the sensitive clay of Quebec ? “Almost everywhere,” admits Serge Leroueil, specialist in mechanics of soils and clays.

More specifically, this sedimentary rock furniture 80 % of the valley of the St. Lawrence river.

“These clays behave like other clays. We are able to build houses and roads. But, in the case of landslides, these sensitive clay can be recast, ” said Mr Leroueil.

Oil

“It is a material that is solid at the start. Then, when it is reconfigured, it becomes like oil, and it flows “, he says. This phenomenon causes several small landslides each year.

“It is also possible that there might have large sliding field of several hectares,” he admits. These are the slopes near running water, that are most at risk of caving in.

Control

However, the expert ensures that the government has put in place a team specialized in landslide.

“A part of the work of these experts is to make maps of susceptibility to landslides. They are studying and define areas likely to have landslides.

For example, he draws bands near the embankment. The idea is that people can’t build in these areas. All municipalities have access to these cards, ” said Mr. Leroueil.

Number of landslides

In the province

• 2017 : 217 (April to June)
• 2016 : 172
• 2015 : 156
• 2014 : 104
• 2013 : 118

By region this year

• Mauricie : 52
• Centre-du-Québec : 31
• Outaouais : 30
• Montérégie : 29
• Lanaudière : 18
• Capitale-Nationale : 13
• North Shore : 9
• Bas-Saint-Laurent : 9
• The laurentians : 8
• Gaspésie–Îles-de-la-Madeleine : 6
• Chaudière-Appalaches : 6
• Saguenay–Lac-Saint-Jean : 4
• Abitibi-Témiscamingue : 1
• Laval : 1
• Nord-du-Québec : 0
• Estrie : 0
• Montréal : 0