Fighting to breathe in the face of Canada’s wildfire emergency


 
11 August 2017

published by https://www.newscientist.com


Canada - By Mika McKinnon in Kamloops, British Columbia

It’s stiflingly hot and I’m trapped inside a dome of smoke. I know I’m in a river valley nestled within mountain ranges, but the visibility is cut so low that I can’t see any of the dramatic peaks that dominate landscapes across British Columbia. It’s the worst documented wildfire season since 1958, and smoke is an omnipresent and unwelcome companion.

“We have a very significant fire season unfolding,” says Daniel Perrakis, a fire research scientist at the Canadian Forest Service. It’s the largest area burned since the advent of modern fire-suppression and fire-management techniques, he says. Over 591,000 hectares have burned so far.

I’ve left my coastal home in Vancouver and travelled inland to support evacuations, joining the swarms of volunteers being deployed to help.

Shifting winds and an atmospheric wall of high pressure have funnelled smoke into the city of Kamloops, filling the air with an unprecedented 684.5 micrograms of fine material per cubic metre. That’s nearly 70 times more than the World Health Organization’s guidelines for safe exposure limits.

My eyes sting when I walk outside, and I feel the throb of a headache coming on if I dare walk as far as the street corner. Even indoors, the smell of smoke whispers through the ventilation systems until it clings to everything. I woke up to ash on my toothbrush, large black flakes against white bristles.

Fuel to the fire

The story of how things got like this is a slow-speed disaster of climate change, a beetle invasion, and the unintended consequences of well-meaning policy gone wrong.

British Columbia is a mountainous, highly forested province in western Canada. More than half of the province is forest, with lodgepole pine dominating every ecosystem except the alpine tundra. “It’s a tree that is really everywhere in BC,” says Perrakis.

Over the past century, the forest industry has transformed native forests into denser, more homogenous stands by suppressing fires and selectively replanting the most economically valuable species after harvesting. “They weren’t nefarious policies at the time, based on what was known,” says Perrakis.

But one unintended recent consequence has been a province-wide bark beetle outbreak that has devastated the region’s forests – with the dying trees heightening the fire threat.

The dense, homogenous stands of lodgepole pine allowed native mountain pine beetles to spread quickly, while a changing climate reduced the severity and duration of cold winters that historically kept the beetle population in check. The infestation hit its peak between 2006 and 2008, although it has begun to slow down in recent years.

I’ve grown accustomed to seeing the once-green mountain slopes spotted with beetle-killed trees: first, one pine turns red as it dies, then more and more follow in speckled waves. Between six months and four years later, depending on individual circumstances, the red needles drop, leaving trees that look like grey, dry skeletons. Now, over 11 per cent of the province is covered in a forest graveyard of dead trees.

Red hot

The dead trees in the “red attack” phase are already known to pose a high fire risk. “We saw fire spread rates two to three times higher in these red-attacked stands,” says Perrakis. Fires burned quickly through the dry tree crowns, racing ahead of firefighters’ attempts to contain and control them.

But starting in around 2011, forests became dominated with the grey tree skeletons – and we don’t yet fully understand how this “grey attack” phase affects wildfires. The situation is complex, with various competing factors either helping or hindering fires.

Without needles, fires no longer spread through forest crowns, but “underburns” racing along the ground are still common as new plants take over the forest. Fire-resistant aspen are taking over some hillsides, whereas highly flammable black spruce is growing in others.

Now when a fire starts, it spreads through a new mix of plants, and the dry wood of the beetle-killed trees adds to fire intensity and smoke production. “The dead trees fall over much more easily, sometimes even with just a breath of wind,” says Perrakis. This increases the danger to crews working in these stands.

Going on burning

This year in British Columbia, over half a million hectares have burned since 1 April, and with 126 fires still burning, that number may keep growing before the snows come. With slow starts to milder winters, that might not be until December. And we have no guarantees that this same disaster won’t unfold again next year, or the year after that.

Sunlight filtering through the smoke creates a perpetual golden hour and dampens shadows, making me feel trapped in a single moment at which time is standing still. It’s hard to remember the world is passing by outside our smoky bubble.

During the drive home, we pass through a recently burned area. Helicopters with water buckets cross the highway, dumping their load on fires I can smell but not see. Hillsides are stained red with fire retardants, remnants of lines drawn to keep the flames back. Some of these efforts worked. Others didn’t, charred homes silent testaments to battles lost. Smoke thins over the 500-kilometre journey home, but never disappears.