November 3, 2022
ITI employees take field trips too.
On October 6, 2022, the NWT Geological Survey’s (NTGS) permafrost science team, including Steve Kokelj, Ashley Rudy, and Niels Weiss took their colleagues on a Yellowknife permafrost tour.
The tour was a repeat of a similar presentation made to a group of Senior federal Directors and ADMs in July.
As climate change impacts an ever-growing number of systems throughout the NWT, understanding and managing the effects of permafrost thaw is increasingly important.
During the tour, ITI staff learned that permafrost is a thermal phenomenon, representing ground frozen for two or more years. Its makeup is variable and can include soil, rock, and most importantly, ice!
The thaw of ice-rich permafrost is of particular concern because when the ice melts, a void is left behind, leading to subsidence which can profoundly affect northern landscapes, ecosystems, and infrastructure. Therefore, it will be increasingly important for northern governments, and decision-makers to consider the expertise of permafrost scientists and engineers in their practices, policies, and strategic planning.
Among the many permafrost-related projects and initiatives underway in the NWT, several monitoring sites record changes in ground temperature and seasonal thaw depth in response to changing climate, or as a result of natural or human-induced disturbance. The permafrost science team is also examining how changes might affect permafrost by manipulating various environmental variables (such as summer rain and winter snowfall) at experimental sites near Yellowknife.
Niels Weiss kneels in front of multiple ground temperature monitoring stations at a permafrost study site near Yellowknife.
While some of the permafrost features the group visited may be subtle, such as a lithalsa (an elevated ridge created by the formation of ice in the subsurface) beside the Yellowknife River day use area, others are striking. For example, an older, abandoned section of the Ingraham trail near town is a compelling illustration of what can happen when infrastructure succumbs to the degradation of underlying permafrost. Variation in the thawing of ice-rich permafrost has caused several metres of differential settlement leading to the formation the “roller coaster road” shown below.
ITI staff climb the rise of a lithalsa at the Yellowknife River to learn how the formation of, and subsequent thaw of permafrost can shape the landscape
The effects of permafrost thaw on the road are evident in this no-longer-used section of the Ingraham Trail.
Steve Kokelj and Ashley Rudy explain how organic materials can insulate the permafrost causing peatlands to respond differently to changing air temperatures. Understanding permafrost terrain is key to making better land-use decisions.
If you are keen to learn more about permafrost in the NWT, you can read A History of Water and Ice: A Field Guide to Permafrost and Environmental Change in the Yellowknife Area, Northwest Territories.
Read about the “Rivers of Change” Story map in our blog from June 30.