The boreal forest covers a third of Canada, stretches across seven provinces and three territories and is home to 2.5 million people. And it's becoming more volatile.
After wildfires roared into this town of 7,000 last Sunday, the Premier called it the disaster of a generation. All told, 485 homes and businesses were razed or heavily damaged. Residents asked why there had been no warning; officials said the fire simply moved too quickly.
Research, however, suggests a fire like this was inevitable, and that it will happen again. The forests are getting warmer and drying out, becoming more fire-prone; they're being hit by more lightning storms, which start 35 per cent of fires; and they're being attacked by the mountain pine beetle, which is migrating steadily eastward, killing trees and making them more flammable.
As a country, Canada spends $800-million annually battling forest fires, excluding the cost of rebuilding what they destroy. It's an expensive struggle that grows more difficult with each year.
"I think it's consistent with what we expect from climate change. We've already seen increases in fire activity in Canada," said Mike Flannigan, a University of Alberta wildland fire professor and Canadian Forest Service researcher. "How we deal with fire in the future is going to have to change from what we've been doing in the past."
The Slave Lake fire took hold on Saturday east of town. Crews began attacking it with water bombers, but it spread quickly, forcing the evacuation of 266 rural residents of Mitsue, about five kilometres east of Slave Lake.
"I saw the smoke suddenly come up. That was it," said Bud Sunderman, 64, a retired mill worker who lost his home of 40 years. "Everything else you have, pictures and stuff, is all gone. All the keepsakes. All the memories."
A day later, crews still thought two nearby fires would miss Slave Lake. Then the winds picked up, surprising fire officials gathered in the town hall.
"We saw a reflection of fire on one of the walls, and we looked behind us and one of the businesses behind us was on fire," said Karina Pillay-Kinnee, Slave Lake's mayor.
They ran from the building, which itself burned down.
The province told the mayor to evacuate, but the fire had forced the closure of nearby highways. Winds had spiked to 100 km/h, sending burning debris raining down while feeding oxygen to the fire and grounding water bombers. The fire advanced unchecked.
Local Mounties - seven of whom lost their homes - scrambled to get residents out.
"I had no idea the fire was that close. No clue. Then all of a sudden it jumped the highway and there it was," said Jeff Bartlett, 51, who lost his home. "It was just all chaos from then on."
Residents were told to take refuge in parking lots and on the beach. Fire crews, some of them volunteers, moved to save what they could - in some cases bulldozing houses that weren't burning to create a firebreak.
One highway was reopened later in the evening and people fled. A week later, residents are still upset, asking why there was no notice.
"The thing I'm most angry about is that by the time they evacuated, the fire was already in town," said Terrence Haynes, 23, who fled Mitsue with his wife and child only to flee Slave Lake the next day.
On Wednesday, the mayor visited evacuee centres for the first time. She wept. She bristles at questions about the response, pointing out that no one died in Slave Lake and they had very little time to act.
"We all responded the best we could," Ms. Pillay-Kinnee said.
Many residents say an earlier voluntary evacuation would have reduced the risk and allowed them to grab some of their belongings. The mayor said she didn't want to "put them in a situation that's unnecessary," and provincial officials agree.
Alberta has pledged $50-million to fund temporary housing and one-time payments of $1,250 to evacuated adults and $500 to evacuated children. That figure will almost surely grow and will be shared by the federal government.
So far this year 264,000 hectares have burned in Alberta, three times the 2010 total. On Friday afternoon, a pilot was killed when one of about 120 helicopters fighting fires in the province crashed. His name wasn't released. A provincewide fire ban is in effect this weekend.
Alberta Municipal Affairs Minister Hector Goudreau, who oversees the Alberta Emergency Management Agency, said he's proud of the response of both planners and fire crews, but added that the province will review how it responded to the Slave Lake fire.
"This one's going to really force us to look at our processes," he said.
In the coming years, provinces can mitigate fire risk by cutting down boreal forest to create a buffer zone, hiring more fire crews and fire-proofing homes through renovation. All are costly.
Some provinces are also moving from fire "suppression" to "management" - controlled burns, which are risky.
British Columbia implemented many of these options in overhauling its fire strategy last year, citing climate change as a factor.
"Almost annually, we're crossing new [fire]thresholds," said Brian Simpson, director of B.C.'s Wildfire Management Branch. "All the numbers speak to it."
Alberta fire crews are slowly following suit, and about 300 trained in B.C. last year.
Population sprawl, the pine beetle and climate change are all affecting the fire season, Mr. Simpson said. And bigger fires release more carbon, fuelling a degrading cycle. Slowing climate change is the best long-term solution, Dr. Flannigan said.
Officials in Alberta, however, aren't so quick to link their increasing forest fire problem to climate change.
"I wouldn't relate [Slave Lake]to a situation where we're suggesting that climate change is an issue going forward. I'd relate it to a one-off," said Mel Knight, Alberta's Minister of Sustainable Resource Development.
Academics disagree. Several published studies have linked climate change and an increased fire threat, the federal government has said. To accommodate that reality, some academics say the aging Canadian Forest Fire Danger Rating System, used to assess risk, needs updating.
Alberta's last major urban forest fire hit the town of Chisholm, just west of the Slave Lake area, in 2001. It destroyed 59 buildings, prompting a review that created the AEMA.
"They didn't learn anything from it. They waited until we were boxed in and said, 'Okay, it's time to go,'" Mr. Haynes said.
Alberta is considering its short-term options.
"Up until now, our existing [fire strategy]has been working well," Mr. Goudreau said. "Are there going to be other communities hit? We hope not, but we can never say never."