El Niño heads north: how tropical weather affects the Arctic

Three Northern communities had their warmest falls on record this year, with many more in the top five — and as El Niño continues, experts say warm and weird weather will likely continue through the winter.

El Niño is a natural weather pattern that starts in the tropics, marked by part of the Pacific Ocean's surface warming up. It often heralds a year of warm and sometimes extreme weather. 

The World Meteorological Organization declared the onset of El Niño in July.

Jesse Wagar, a warning preparedness meteorologist with Environment and Climate Change Canada (ECCC), said it's one of the factors involved in the abnormally warm fall in the North. It was the warmest on record for Old Crow, Yukon; Inuvik, N.W.T.; and, further east, Cambridge Bay in Nunavut.

"It can't all be attributed just to the El Niño years or the La Niña years.... The trend overall is that we are seeing just warming generally," she said.

Over September, October and November, Yellowknife experienced its second-warmest fall on record, as did the Nunavut communities of Resolute Bay and Gjoa Haven. Many other communities in the North had warmer weather than usual as well, including every Yukon community ECCC monitors.

Impacts on the North

For Earl Evans, a hunter and trapper from Fort Smith, this November has been the warmest he can remember. That's led to challenges, as lakes and rivers that should be frozen over by now aren't.

"It takes the person longer and longer to get to where you're going because of the non-freezing. So that's one of the things that kind of delays our schedule and what we should be doing if we're trapping or trying to hunt or access different areas. So it slows the access down to get in the bush," he said. 

Even when it does get cold enough for the rivers to freeze over, if the temperature warms again, it can lead to overflow. The surface ice cracks and water pools on the surface, which can be dangerous for both people and vehicles travelling on the ice.

Evans also said he's seen an impact on wildlife. The warm weather can cause an icy crust to form on the ground, which animals like caribou, bison and foxes struggle to break through to access food. This has shifted the movement of these animals to areas that are more sheltered from the wind and rain.

"It makes it harder for the people that are hunting them, because you go to the areas where you've always hunted, expect to get animals, they're not there and you have to travel elsewhere and you'll burn more fuel and more time. And it makes it more expensive for a person to live in the bush," Evans said.

A warm winter's coming

El Niño typically leads to warmer and drier weather in the North, particularly for the first part of winter. This doesn't mean there won't be days where it's cold or wet, but overall the pattern will lean warmer.

"Living in the Northwest Territories, the weather could be quite dynamic and I don't see why that wouldn't be the case moving through the winter season," Wagar said. "But when we're talking about averages and overall, [it] definitely looks like a warmer than normal winter and a drier than normal winter."

The second half of winter could be more unpredictable, said Hossein Bonakdari, an associate professor of civil engineering at the University of Ottawa.

"Weather models are not [able to] predict clearly the situation of the second part of winter," he said.

"This El Niño can change everything. This is a really unknown situation from [the] scientific part and the prediction part, [and] that can cause a really challenging time for us because we are not able to predict. We feel we will face a novel weather pattern and challenges during the second part of [winter]."

He said parts of Nunavut, such as Baffin Island and along Hudson Bay, may have colder than normal temperatures in the late winter. He also said he's expecting to see ice storms, temperature swings and other extreme winter weather.

Wagar said El Niño shifts storm patterns further north and east than usual, but that weather is complex and exactly what will happen can be hard to predict.

The effects of this year's El Niño are expected to persist into the springtime. Bonakdari said the warm and dry conditions over the winter may lead to a greater risk of droughts or floods in the spring depending on the region. 

"Communities and also municipalities should prepare in the short term for these potentially intense storms, making sure that there is enough food, people have an emergency supply of goods," he said. "Longer term, there should be planning that looks into mitigating [things] like wildfire risks, drought risk going forward into the summer."