A large landslide occurred approximately 650 kilometers south of Inuvik, halfway between Wrigley and Tulita on the Johnson River, about five kilometres from where it meets the Mackenzie River.
The landslide created a lake that is approximately five kilometres across.
Chris Burn is a Northern studies professor at Carleton University who researches permafrost and ground ice in the Western Arctic.
Burn says the number of landslides in the NWT has been increasing since the 1990s.
In September 2009, 25 landslides were recorded near Reindeer Station, and in 2017, approximately 80 landslides in the same place.
Burn says the increase in landslides is a result of climate change.
“In the whole of the Mackenzie Valley, there are pockets where there is lots of ice in the sediment,” said Burn. “Now there is significant warming going on, so in some places, the warming is beginning to melt the ice, and as it melts, it makes the ground unstable. So, where there is a slope, you often have landslides.”
Since the 1960s, Burn says Inuvik’s annual average temperature has been steadily getting warmer.
In the 1960s, the average annual temperature of Inuvik was -9.5C, but in the 2010s the average has been approximately -6.5C and last year it was -4.5C.
“What really concerns me is that 2017 was the second-warmest year ever recorded in Inuvik at -4.5 degrees,” he said.
Burn said another factor contributing to the increase in landslides is an increase in precipitation. In the last 60 years, Inuvik has seen nine of its rainiest years on record.
Forest fires are also on the rise, and they contribute to causing landslides as well.
He said for the most part, as long as people are not near the landslide when it occurs, they are not dangerous. However, they can impact river water quality and fish health.
“People driving their boats on the river will have to avoid certain places, especially close to shore, because at the bottom of these landslides, there is lots of debris like tree trunks sticking out,” he said.
David Huntley, a research scientist with the Geological Survey of Canada, says landslides will always happen in the Mackenzie Valley, but the recent landslide was particularly large.
He added that most of the landslides he has seen are only a few hundred metres across.
Inuvik was built on bedrock, Huntley said, so there is little risk of a landslide occurring anywhere near town.