What's driving the powerful wildfires in the Northwest Territories

Wildfires raging in the Northwest Territories have prompted an evacuation order for the entire capital city of Yellowknife, along with several other smaller communities.

There are more than 230 active fires in the territory, including three near the capital.

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Here's a closer look at what's led to the wildfires, and how the North is becoming more susceptible to them as the climate changes.

Hot, dry and windy

The Northwest Territories, a vast expanse of boreal forest and tundra, are in the middle of an unusually dry summer that began with an unusually hot spring.

"It's been dry and some of these fires have been burning since May," said Mike Flannigan, a professor and wildfire expert at Thompson Rivers University in Kamloops, B.C.

"Some of them are very large, approaching the size of Prince Edward Island."

Overall, Canada has already shattered the record for area burned this season. The N.W.T. hasn't gotten to that point yet, as2014 holds the record for the largest area burned.

But a dry, hot and windy stretch in recent weeks has given the fires renewed strength, Flannigan said, and there's no sign they'll be extinguishedanytime soon.

"For the next 10 to 15 days it will be mostly dry," he said."It's a very active situation."

Flannigan said it's likely that many of the wildfires will continue to burn right through summer andautumn until winter comes.

"Even then, some of these fires over winter go underground and smolder, and when the snow meltsthey pop back up."

Usually, fires are left to burn

Experts stress that large wildfires are a part of the natural cycle in the Northwest Territories and, given the sparse population, they are usually left to burn out on their own.

What makes this year especially challenging is that the fires have threatened so many communities, putting a strain on resources, said Dan Thompson, a forest fire research scientist with Natural Resources Canada.

The hamlet of Enterprise, for instance, was almost entirely wiped out earlier this week when the wind suddenly picked up, causing a wildfire to rapidly spread overnight.

"I think it's fair to say, although our records are fuzzier, that the scale of human impact for wildfire in the territories would be a record," Thompson said.

The evacuation of Yellowknife and surrounding communities comes after the displacement of residents in Fort Smith, Hay River, the Kt'odeeche First Nation, Enterprise and Jean Marie River.

In ending Wednesday's briefing, N.W.T. Premier Caroline Cochrane called the situation unprecedented. "There's no other way to describe it," she said.

WATCH | Yellowknife wildfire evacuees pour into Alberta town:

Yellowknife wildfire evacuees pour into Alberta town after harrowing 700-km journey

1 year ago

Duration 2:55

High Level, Alta., is scrambling to take in droves of N.W.T. residents ordered to leave Yellowknife and other communities as dangerous wildfires approach. Calgary is also bracing to receive as many as 5,000 people.

North disproportionately affected

Across Canada, climate change is making wildfires more powerful, particularly in the North.

Northern Canada and other Arctic regions are warming at three to four times the rate of the rest of the globe, and that means those areas are likely to see even more fires.

"A warmer world means more fire, and longer fire seasons,"Flannigansaid.

In Canada, roughly half of wildfires are caused by lightning and half by human activity. In N.W.T, however, the number of fires caused by lightning is far higher approaching 90 per cent, according to Flannigan.

Research suggeststhe number of lightning strikes in N.W.T. will rise in the years to come, leading to more wildfires.

Scientists have also found thatrecently burned forests in the midst of regeneration are, in the future,more likely to catch fire again, and sooner, given an expected increase in dryer, warmer weather.