Police said a 45-year-old man from Yellowknife lost his life in a collision involving a semi truck while trying to change a tire on Highway 3 at night.
In an update on Wednesday afternoon, RCMP said the collision had taken place 45 km west of the city just before two o'clock that morning. The man has not been identified.
Two other people were taken to hospital with injuries that aren't said to be life-threatening.
Police said the collision occurred when a semi truck came upon several vehicles that had already stopped on the highway.
Two pickup trucks had pulled over to attend to a flat tire on a trailer, while a separate semi truck had stopped on the other side of the road to offer assistance, RCMP said.
"Soon after, a semi truck heading westbound came upon the scene and collided with the parked pickup trucks," police said in a statement, "hitting the victim, who was outside of his vehicle attending to the trailer.
"The victim was declared deceased at the scene."
The two injured people were pickup truck passengers.
Though both semis were carrying fuel, police say there was no spill on the road and neither driver was hurt. The highway reopened later on Wednesday morning.
"Alcohol was not a factor, while extreme cold weather conditions are believed to be a factor," police said.
"The investigation is ongoing. Our thoughts are with the family of the deceased during these difficult times, members of the public who assisted at the scene, and first responders who responded to this accident in very difficult circumstances."
If anyone witnessed the collision, they are asked to contact Yellowknife RCMP at 669-1111.