Skip to content

More mapping of permafrost needed for infrastructure planning

As the territory looks to adapt to climate change, it must map out one of its most critical resources — ice, industry experts say.

Ice is a main ingredient in permafrost, which underlies about 50 per cent of Canada, but in the NWT it affects “just about every community,” said Kumari Karunaratne, acting director of the NWT Geological Survey.

The Dettah ice road shortens the drive for residents between Dettah and Yellowknife. Avery Zingel/NNSL photo

Ice is also a critical component of winter roads and warmer winters are shortening their existence in the NWT, presenting challenges for maintenance and transportation reliability, said Kevin McLeod, assistant deputy minister of asset management for the territory's Department of Infrastructure.

For ice roads and ice bridges, clearly we need mother nature to give us cold consistent temperatures to make (them) as safe as possible,” said McLeod. It’s getting colder later and warming up sooner. As a government and provider of that infrastructure, we need to decide what we should be doing about that.” Options include shifting from reliance on ice roads to all-weather roads, he said.

In the 1970s and 1980s, ice roads lasted between 76 and 80 days. By the early 1990s and 2000s, the ice road season shortened to about 60 days, said McLeod.

In the Climate Change Strategic Framework, the territory has an adaptation strategy to tackle climate change’s effects on infrastructure, said McLeod, an element of which was the construction of the all-weather Inuvik-Tukotoyaktuk Highway.

At the end of the day you need to give the travelling public a reliable transportation network,” he said.

Connecting Whati by an all-weather road will connect a community whose winter road season is shrinking, said McLeod.

In order to provide consistent and resilient networks, we're moving that ice road to an all-season road. Those are the kind of long range strategies that the government is seeing as viable,” he said.

In March, the Mackenzie Valley Review Board issued its approval of the all-weather road to Whati, along with 23 recommendations to manage impacts to the wellbeing of Whati residents and to protect caribou.

In the approval of the all-weather road, the board stated that the project would be built over a permafrost area and require the developer to create a permafrost management plan.

The project is partly proposed to respond to the effects of climate change on the Whati winter road,” the report states.

Unfortunately, climate change could also affect the all-weather road through thawing permafrost and increased maintenance costs and safety risks to users, the report states.

A socio-economic report on Whatì published by the Tłı̨chǫ Government states its concerns about an all-weather road, which include reduced safety, increased pressures from hunting and fishing and increased industrial development.

The report lists access to cheaper goods, cheaper and more reliable transportation solutions, jobs and economic development and increased mobility to other communities as benefits.

As new roads are built, the GNWT is working with experts to understand how permafrost will impact road infrastructure in the North, where climate change effects are more visible, said McLeod.

We are leading the charge in a lot of cases in terms of our research and sponsoring of test sections and think tanks to say, 'This is our real life problem. What are some real life solutions?'” said McLeod.

The territory requires more data to understand the full extent of permafrost structures and which land is at greatest risk of permafrost slumping and thaw, said Karunaratne.

Frozen ground provides stable building conditions, but changing thermal conditions melt the ground and threaten structural integrity, she said.

Permafrost is not just a few feet,” she said. Above the treeline, it can be hundreds of metres thick.

Its integrity is affected by air temperature, the presence of vegetation, duration of winter season and overall precipitation in winter and summer.”

Permafrost engineers design infrastructure with foundations that suit the thermal makeup of permafrost to keep it stable, she said.

If we don’t know how the climate is going to change and how it will affect the permafrost, it’s very hard to design a road to withstand a climate that we have not seen before,” said Karunaratne.

The road between Yellowknife and Bechoko is one example of “ice rich permafrost” structures, called lithalsas, which are caused by the expansion of ice beneath the surface of the soil

The frost heaving they cause mean the highway will constantly require maintenance, said Karunaratne.

Planning infrastructure on a precarious landscape requires mapping and characterizing permafrost features in depth, she said.

In the new GNWT climate change strategy, permafrost is mentioned 105 times. However, there is limited mapping, said Karunaratne.

This year, the Canadian Permafrost Association formed to foster communication between permafrost scientists and governments, communities and engineers.

Remote sensing can be used to identify permafrost formations like lithalsas and find out where ground is particularly vulnerable, said Karunaratne.

Studies are now identifying examples of “mega slumps which are the size of downtown Yellowknife, which are much much bigger than we’re used to seeing,” she said.

Students studying the northwestern arctic by satellite are mapping active slumps, which line up closely with the last ice sheet that covered North America.

It shows where there is ground ice and we should be really careful about choosing where we disturb the landscape,” said Karunaratne.