In late October, a major landslide occurred in northern Quebec, washing away about 16 million cubic yards of soil and vegetation and reigniting fears about climate change.
Posted at 5:00 am
Jean-Thomas Léveillé The press
A section of about 900 by 900 meters of bottom, or almost a square kilometer, was thus submerged in a tributary of the small Whale River, which is located about halfway between the Inuit communities of Kuujjuarapik and Umiujaq on the coast of Hudson Bay.
“It’s a very big landslide,” Eric Drolet, regional director of the Department of Public Safety for Nunavik, Chaudière-Appalaches and the Capitale-Nationale, told La Presse.
Aerial photos released on social media, which La Presse was able to authenticate, show large areas of gray land on either side of the river, filled with debris.
PHOTO FROM FACEBOOK
The landslide occurred in Nunavik in late October.
The event, which would have happened between October 29th and 31st, apparently had no human consequences as the sector was uninhabited.
On the other hand, it will disrupt the hunting and fishing of the Inuit communities as well as the neighboring Cree community of Whapmagoostui.
“We need to demarcate an area where access is prohibited,” Whapmagoostui community spokesman Joshua Kawapit told La Presse as a security measure. “It will affect the use of the territory,” he says
Difficult access
The winter that is already beginning in these latitudes makes access to the site of the landslide, about 20 kilometers inland, more difficult.
“The snow is starting to fall, it will be difficult to check on the ground, it will probably not be before spring,” says Eric Drolet, who explains that analyzes are currently being carried out using satellite imagery and, for example, by remote sensing using lidar, allowing the relief of a sector to be represented.
The regional government of Kativik, the local government responsible for Nunavik, is “mobilizing multiple resources to reach the exact location where the landslide occurred,” its spokesman Rocío Valencia said.
“We only have a preliminary amount of information at this point,” she added, adding that the authorities of the three affected communities held a meeting on Thursday and would provide more information to the population as soon as possible.
Climatic changes
It’s too early to determine with certainty what caused this landslide, but it’s a phenomenon expected to increase with climate change, experts warn.
The increase in “heavy precipitation events” caused by global warming is likely to lead to an increase in landslide activity, explains Pascale Roy-Léveillée, Associate Research Chair in Permafrost at Nunavik from Laval University, who is also affiliated with the Center for Northern Studies.
“Often, landslides occur in situations where there has been abundant rainfall, water infiltration, and somewhat more aggressive erosion,” she explains, adding that the soils of the Kuujjuarapik and Umiujaq region are particularly sensitive to marine clays.
“These are marine deposits of very, very fine sediments” dating back to the last Ice Age when the area was below the water level of the Tyrrell Sea, “an enlarged version of Hudson Bay,” explains Ms. Roy-Léveillée.
These soils have the potential to “liquefy” when destabilized, she continues.
Northern Quebec has also experienced warmer summers, shorter winters and wetter autumns and springs since the 1950s, says Angelica Alberti-Dufort, knowledge transfer specialist at Ouranos, a consortium on regional climatology and climate change adaptation. “Climate projections show that this will continue into the next century,” she says.
These phenomena not only directly favor the “subsidence” or subsidence of the ground, but also promise to cause the thawing of the permafrost, which is another cause of landslides, explains Ms. Alberti-Dufort.
With climate change, this will generally happen more frequently.
Angelica Alberti-Dufort, Knowledge Transfer Specialist at Ouranos
Another gigantic landslide occurred in April 2021 near Kuujjuarapik and Whapmagoostui, this time along the Great Whale River; a 1.8 kilometer by 500 meter piece of land had sunk into the creek.
This landslide, estimated at 45 million cubic meters, was then considered the second largest in Quebec’s history, after Portneuf’s in 1894.
Learn more
+1.5°C warming observed in northern Quebec between 1948 and 2016, compared to 0.5°C in the Saint Lawrence Valley
Source: Ouranos
The permafrost line in Quebec has shifted 130 km north over the past half century
Source: Center for Northern Studies