19,000 homes in Quebec threatened by landslides

The populated areas of Quebec are increasingly prone to landslides due to climate change. As many as 19,000 homes are under surveillance as they are located in government-listed high-risk areas.

• Also read: Landslide in Saguenay: the relocation of the victims is complete

• Also read: Chicoutimi: 18 people evacuated after two landslides

note : To find your address directly, carry out a search with the magnifying glass on the map.

Legend :

Stay more at risk

Ground movement reported since January 2007


The map and analysis of buildings in the landslide prone areas were created from a combination of two separate files.

The first (red zone), established by the Ministère des Transports (MTQ), locates the parts of the territory where the landslide standards mandated by the Quebec government must apply. The identified areas are more prone to ground motion due to several characteristics, including the nature of the ground or elevation.

The second file contains all Quebec addresses denoted by a black dot. This is an official government data source. A point usually corresponds to the center of the building or the main entrance door. The Journal has highlighted all points/addresses in the landslide prone areas.

The yellow dots correspond to ground movements reported since January 2007. They come from the Ministry of Public Security and are available in open data.

caution :

*Even if it doesn’t appear on the map, it’s still possible for a building to be in a higher risk area and vice versa.

**The journal found several discrepancies between the official address data and the map generator used for this project. After verification, official sources provide more precise information about the location of a building.

*** This map has no legal value, professional opinion is required to determine whether or not your building is in an area more prone to landslides.

The large landslide that swept away a residential home at the base of a cliff in the La Baie district of Saguenay on June 13 forced the evacuation of 76 homes in the same area. Unfortunately, some owners will never be able to return to their homes because the risks are too high.

To date, 41 municipalities manage sectors located in the heart of areas prone to landslides. According to The protocolno fewer than 19,000 homes and more than 1,000 commercial units are currently in these areas across Quebec, not to mention community infrastructure, institutional buildings and resorts.

These dwellings are mostly built on “sensitive” clay soils, which tend to move when disturbed.

The government ensures that these places are monitored and preventive measures are implemented.

Climatic changes

These natural events, which are affecting Quebec’s built heritage and the safety of its population, are expected to increase at an accelerated rate due to the climate crisis, experts say.

“Indeed, the vegetation is changing, just like the soil,” explains Alain Bourque, executive director of Ouranos, a consortium for regional climatology and climate change adaptation.

According to the Canadian Geoscience Education Network, river erosion and increased water pressure in the ground can trigger subsidence “particularly during heavy rainfall or rapid snowmelt.”

“That means a shift that should have happened perhaps in 2085 could happen now. We can imagine that by 2100 there will be many more people who will experience landslides because the ground has become unstable.

rank town, village Housing
1 Gatineau 5360
2 Shawinigan 2425
3 Saguenay 1895
4 mask 827
5 Blainville 821
6 Three Rivers 710
7 Chute aux Outardes 558
8th alma 512
9 Sainte Therese 512
10 Baie Comeau 472

Source: Quebec Department of Transportation and Department of Energy and Natural Resources

human intervention

This phenomenon is in addition to human activities, “such as excavation and construction work,” which typically act as the primary trigger or exacerbating factor in landslides.

“Everyone wanted a nice view from the top of the embankments,” emphasizes Professor Emeritus Serge Leroueil. “Back then we knew less about the risk. »

Geotechnician Mr. Leroueil thinks it is “plausible” that climate change is increasing the risks. Increased precipitation can cause ground movement, he says, but he adds nuance; these are mostly “superficial”.

climate analyzed

For its part, the Ministry of Public Security is ensuring that its analysis and monitoring now includes climate-related risks.

“Advances in research into the effects of climate change on certain types of landslides now make it possible to take these parameters into account,” stresses Marie-Josée Montminy of the Ministère de la Sécurité publique.

NUMBER OF NON-SLIP PROPERTIES IN QUEBEC

18,000 Building*

19,000 residential units

1000 business areas

  • A building can contain multiple units
  • The number of dwellings built in restricted areas may change over time
  • The risk levels associated with landslides vary within the same stress zone. The probability of being affected by a landslide decreases the farther away you are from an embankment.

Sources: Departments of Municipal Affairs and Housing, Public Safety, Natural Resources and Transport

Surname address units description
Chartwell Domaine Cascade 695, 7th rue de la Pointe
Shawinigan
265 Home for autonomous retirees
Chavoin Terrace 23, rue de la Soeur-Jeanne-Marie-Chavoin
Gatineau
206 accomodation
Fontainebleau Sunrise apartment building 50, Boulevard des Chateaux
Blainville
103 Home for autonomous retirees
Crystal Residence 4715 Boulevard de la Grande Baie South
Saguenay
62 Home for autonomous retirees
ELK Property Management Limited 45, rue Charles-Albanel
Gatineau
60 accomodation
40 Louis-Vadeboncoeur 40, rue Louis-Vadeboncoeur
Saint Charles Borromee
36 accomodation
Housing cooperative 400 Riel 400 Riel Blvd.
Gatineau
35 accomodation
Residence Mont Bleu 100 Boulevard du Mont Bleu
Gatineau
35 intermediate resource
CHSLD Isidore Gauthier 5731 Nordbrückenallee
alma
30 Home for non-autonomous retirees (including CHSLDs)
my home 18, rue Hamel
Gatineau
26 accomodation

Source: Quebec Department of Transportation and Department of Energy and Natural Resources

VERY PRECIOUS TO THE STATE

Over the past decade, Quebec has spent $71 million on financial assistance programs for landslide victims and conducting ground movement prevention efforts. “Under the emergency relief programs, a total of more than $32 million has been paid to individuals, rental property owners and businesses related to ground movement files,” said the spokesman for the Ministry of Public Safety (MSP). , Marie-Josee Montminy. In addition, 13 landslide prevention projects valued at $39 million have been completed or will be completed by 2025.

HUNDREDS OF INCIDENTS

For the past five years, an average of 182 landslides have been registered each year, particularly in densely populated regions. Reports are identified by the ministry as “possible threats to life or property.” Movements mostly take place outside of the areas shown on the government map. In the past 10 years, a total of 369 individual cases have been opened under the homeowner’s financial assistance programs. On average, $87,000 was paid per file. Public infrastructure such as roads are also victims of these settlements.

INCREASED MONITORING

The Ministry of Public Security ensures that a risk analysis for the built environment is carried out by its experts to “ensure safe rural development”. The government determines the vulnerable zones, which are then disseminated through mapping in the urban environment. “This makes it possible to identify situations of concern where mitigation measures are deemed necessary. Depending on the situation, financial support can be offered to the community and affected citizens to rectify the situation,” explains MSP spokeswoman Marie-Josée Montminy. Municipalities are obliged to integrate it into their development plan. Quebec may request changes for public safety reasons.

NO DEPRECIATION… FOR THE FIRST TIME

In 2018, Quebec City’s Altus Group conducted a study of the market value of land in La Baie located within landslide stress zones. Conclusion: There was no significant impact on the selling price. The panoramic view and the quality of the materials are the winning elements. In several cases, however, the location certificate did not clearly state the inclusion of housing in the zone, as did the property advertisements, which emphasized the view. “If market participants … ignore the possibility of slippage occurring, the impact on prices may be skewed,” the report states.

VULNERABLE PEOPLE

According to the list of buildings located in landslide-prone restricted areas, the main high-density buildings are senior residences and housing cooperatives. For example, the Chartwell Domaine Cascade residence in Shawinigan has 265 units and is in a red zone, according to the Department of Energy. In Alma, the CHSLD Isidore-Gauthier can also be found in one of the risk areas. Resorts, such as the Chalets sur le Fjord in L’Anse-Saint-Jean, are also located in these areas, as well as institutional buildings such as schools and day care centers.

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CREDITS

Written by Nicolas Lachance

Research, data collection: Philippe Langlois, Bureau of Investigation

Design, integration, data visualization: Cécilia Defer

Directed and edited by Charles Trahan

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