More than 20 centimetres of snow could fall in some parts of the Yellowknife region by mid-Friday, Environment and Climate Change Canada warned on Thursday evening.
Federal forecasters issued a weather alert just before 4pm on Thursday and updated their guidance as snow squalls began later in the day. At least 10 cm of snow is expected overnight, while some places could see more than double that amount over the next 24 hours.
"Snow has developed over Yellowknife and will continue overnight into Friday," the department wrote in an advisory published just before 9:30pm on Thursday.
"The snow is expected to be enhanced by lake effect snow, which will result in some areas seeing upwards of 20 cm by Friday afternoon.
"Prepare for quickly changing and deteriorating travel conditions. Visibility may be suddenly reduced at times in heavy snow."
Environment and Climate Change Canada said snow squall warnings are issued when bands of snow form that produce intense accumulating snow or near-zero visibilities.
Meanwhile, to the west in the Dehcho, Wrigley was under a snowfall warning on Thursday night. Up to 15 cm of snow was expected. Elsewhere, most parts of the territory were expecting at least flurries overnight.