Snow is expected to intensify across parts of northern Canada as September comes to an end, with some remote areas forecast to receive up to 40 centimetres from a developing low-pressure system.
The heaviest accumulations are expected across a broad northern corridor extending from the eastern edge of Great Slave Lake toward areas north of Baker Lake in Nunavut.
Snowfall may also spread farther east toward Baffin Island as the system moves through the North.
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Where the heaviest snow is expected
Forecast guidance indicates that the storm will deepen as it tracks north into southern Nunavut, drawing moisture northward from lower latitudes.
That moisture is expected to fall as heavy, wet snow on the colder side of the system.
The highest local totals are forecast in remote areas, where snowfall could reach as much as 40 centimetres by the time the system clears.
The forecast does not indicate that all northern communities will receive the same amount.
Snowfall totals will depend on the storm’s exact track, local temperatures and how long precipitation remains locked in as snow rather than rain or mixed precipitation.
A sharp change after unusually mild conditions
The system follows an unusually mild stretch in parts of the Northwest Territories and southern Nunavut.
Fort Reliance, N.W.T., reached 20.4 C on September 21, according to the forecast report tracking the system.
The contrast between that warmth and the approaching cold air is helping create the conditions for a significant early-season snowfall event.
Environment and Climate Change Canada’s forecast for Banff National Park also shows how quickly snow levels can fall in higher terrain at this time of year.
The agency forecast 2 centimetres over sections of the Icefields Parkway, with the snow level dropping to about 1,900 metres overnight.
What the snow could mean for northern travel
Heavy early-season snow can create difficult conditions for aircraft, highway users and remote residents, particularly when wet snow combines with wind and falling temperatures.
Wet snow is heavier than dry powder and can cling to power lines, structures and vegetation.
If temperatures fall quickly after the storm, slushy surfaces may freeze and create additional hazards.
Drivers and travellers in affected areas should check local forecasts and transportation advisories before setting out.
Conditions in the North can change quickly, and weather impacts may be more severe outside larger communities.
- Check Environment and Climate Change Canada forecasts before travelling.
- Allow extra time for reduced visibility and snow-covered surfaces.
- Carry winter clothing and emergency supplies when travelling in remote areas.
- Follow local airport, highway and community advisories.
Will the snow spread farther south?
Snow typically begins moving southward across Canada during October, but the timing varies considerably from year to year and from region to region.
The current event is concentrated mainly in northern and elevated areas.
It should not be interpreted as a forecast that major southern Canadian cities are about to receive comparable snowfall.
In the Rockies, Environment and Climate Change Canada is forecasting milder conditions after the current high-elevation snow, including sunshine and temperatures rising into the low 20s in Banff National Park early next week.
What happens next
Forecasters will continue to refine snowfall totals as the low-pressure system develops and moves across the North.
The most important changes to watch are the storm track, the position of the rain-snow line and wind conditions behind the system.
Those details will determine whether the heaviest snow remains in remote terrain or affects additional communities and transportation routes.
The late-September storm is also a reminder that a mild start to autumn does not prevent an abrupt shift to winter-like conditions in northern Canada.
Frequently Asked Questions
Where is the heaviest snow expected in northern Canada?
The heaviest snow is forecast from the eastern fringes of Great Slave Lake toward areas north of Baker Lake in Nunavut, with snowfall potentially extending toward Baffin Island.
How much snow could fall?
Some remote areas could receive up to 40 centimetres, although totals will vary depending on the storm track and local temperatures.
Is the snow expected to affect all of Canada?
No. The most significant snowfall is focused on northern and elevated areas, while many southern regions are not forecast to receive comparable amounts from this system.
Why can early-season snow be heavy?
Autumn storms can draw on relatively deep supplies of atmospheric moisture before the colder, drier conditions of mid-winter become established.
What should travellers do during the storm?
Travellers should check official forecasts and transportation advisories, allow extra time, prepare for reduced visibility and carry appropriate cold-weather emergency supplies.
Fact-Checked: Key forecast details and climate context were checked against Environment and Climate Change Canada information and current forecast reporting.
Disclaimer: Snowfall amounts and storm tracks can change, so readers should consult local official weather alerts before travelling.