The 'human-caused' question: why reckless humans aren't to blame for BC's fire crisis

A bird touches a power line and explodes in a ball of feathers and flame. Its carcass falls to the ground, setting the dried-out brush ablaze.

Another “human-caused” fire has begun.

Every year, hundreds of wildfires in British Columbia are declared to be “human-caused.” Such statements regularly prompt declarations that if only people behaved themselves, wildfires wouldn’t be quite so disrupting. Others increasingly use the statistic to conspiratorially blame wildfires on “arsonists.”

But as our unfortunate bird demonstrates, many fires blamed on humans aren’t actually related to reckless behaviour. Instead, humans play a much more complex and varied influence on wildfire ignitions than many realize. And that has a bearing on how—and when—we seek to prevent such blazes.

Human or nature?

The causes of wildfires might be wide-ranging and diverse, but detailed public data on those causes is extremely limited in British Columbia.

Fires are publicly assigned to one of two broad categories: “natural-caused” or “human-caused.” Almost all fire causes are lumped into these two very-large buckets. For the public (and reporters), that’s often all the data and information that is available.

The breadth of the human-caused and natural-caused categories makes it relatively easy for officials to classify most blazes. The general rule is that if lightning is believed to have started a fire, it’s “natural.” No lightning? It’s almost certainly categorized as human-caused.

The involvement of lightning is itself increasingly easy to pin down now. A quarter century ago, the federal government launched the Canadian Lightning Detection Network. It now has more than 80 sensors across the country and can detect up to 45,000 lightning strikes each hour, according to a government website.

(An aside on how that works: the sensors detect lightning’s electromagnetic pulse and use it to determine its strength, polarity, and time of impact. That information is sent south, to Colorado, where it’s entered in the database of the National Lightning Detection Network, a system owned by a private company called Vaisala Group. The network uses readings of the same lightning strike from three different sensor locations to triangulate the location. The location is then relayed to a variety of clients—including Canadian governments. The data is useful for a range of companies for which thunderstorms pose a risk. Vaisala says those include forestry, utilities, airports, telecommunications and ‘explosives handling’ operations.)

So if lightning was detected in the vicinity of where the fire broke out—and especially if there is no convenient access to that site—officials know it is probably to blame. If there was no thunderstorm nearby, the fire will probably be designated as “human-caused.”

There’s a bit more to it than that, but that simplicity is key in the days and hours after a fire breaks out, when an on-the-ground investigation might be impossible but officials, residents and the media want to know the source of a blaze.

A hundred flavours of human fire

In BC, about 40% of all wildfires are “human-caused,” though that figure fluctuates depending on weather and lightning conditions for any one year.

But we have much worse public data on how, exactly, humans are causing the 40% of fires blamed on people.

That is, in part, a symptom of the BC government’s aversion to sharing public data. But it’s also because the exact cause of every fire in BC isn’t investigated. With more than 1,500 wildfires most years—many in extremely remote areas—intensely probing the cause of each would be incredibly time consuming and expensive. It wasn’t until March of 2022 that the devastating White Rock Lake fire the previous year was officially deemed to have been caused by lightning.

Officials do privately classify fires with more detailed information when it is available, according to a BC Wildfire Service (BCWS) spokesperson. So a report on a fire believed to have been started by campers might classify it as “recreation > camping”. But that information is not publicly posted online and The Current was unable to find a breakdown of various causes and their frequencies in BC—or anyone who could point us in the right direction. BCWS declined to provide a more-detailed breakdown of human-caused fires, saying such information was not readily available. (They noted that time is currently limited because of the fire situation in the province.)

BC’s wildfire service says common causes for human-caused fires include “open burning; vehicle and engine use; industrial activity; fireworks, sky-lanterns, outdoor flame lighting, discarded cigarettes, and arson.” But what percentage each represents is unclear.

Alberta—which releases much more fire-cause information—provides more specific data: last year, about one-third (36%) of all human-caused fires were deemed linked to “recreation.” That was the highest percentage. The rest were split across a variety of broad categories. The next largest classification group was “residential,” with 119 fires cited.

BC’s human-caused fires are likely to share some similarities with its neighbour, while also departing in substantial ways due to differences in geography, economies, and population distributions.

There’s also a difference between the human/nature breakdown: Alberta’s worst fires occur in the spring, when the vast majority of fires are “human-caused”; BC blazes tend to do their damage in the mid-summer, when lightning-caused fires are most prevalent.

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Three types of human fire

Human-caused fires can roughly be sub-divided into three broad categories: recreation, industrial, and residential/agricultural.

Recreational

When many people think of human-caused blazes, they tend to imagine the fires that Smokey The Bear says you can prevent.

Those include poorly discarded cigarettes (or joints), unattended campfires, target shooting of incendiary devices, careless backyard burns, and even baby gender reveals. If you’re dumb, careless, or intoxicated enough, there is almost an infinite number of ways to set a tinder-dry forest on fire.

That said, the larger culprits aren’t always the most obvious. Although one should be careful where one discards cigarettes, wildfire scientist Mike Flannigan said such ignitions are actually relatively rare.

“You hear a lot about cigarettes but cigarettes don’t start many [wildfires],” he told The Current.

One of the more common recreation ignition sources comes from the exhaust pipes of vehicles— especially ATVs and dirtbikes travelling on off-road trails. Hot tailpipes on vehicles of all sorts have also been known to ignite dry grass—especially if those vehicles remain in one place for a significant amount of time.

Industry

But a huge number of human-caused fires aren’t caused by people having too much fun, but by those working in the province’s sprawling forests, or the equipment they’re using.

The BC Wildfire Service website hints at the forest fire risk posed by a whole slew of commercial and industrial activity. The movement of trains, operation of power lines, and outdoor trades-based activities can all cause sparks that ignite fuel and start forest fires.

Indeed, while the public hears little about it, managing summer industrial activity is a massive part of how BC manages fire risk. One example can be seen in the fire danger ratings and maps with which many are familiar. Those are not just a service for the general public.

Local fire danger ratings play a legally defined role in the regulation of risky activity in the province’s sprawling forests. The forest fire risk in a local area determines when industrial work defined as “high risk” can take place. When the fire risk is extreme, high-risk work between 1pm and sunset is banned. If that extreme fire risk continues for three days, that curfew is extended to the entire day.

That “high risk” activity includes rail-grinding, clearing land with machinery, the use of spark-producing cutting tools, disk-trenching, and even the mowing of grass along roadways. BC’s oil and gas industry, and other activities in remote, heavily forested areas, are also seen as a potential source of fires. And a whole slew of forestry-related work is also subject to the restrictions. It’s up to anybody undertaking such work to know their local fire risk and the attached limits on activity.

The danger from industrial activity is so large that the threshold for the restriction of industrial activity is actually lower than for the banning of campfires, according to the BCWS website.

Twice in the last decade, CN Rail has been fined millions of dollars for its role in sparking major wildfires. Residents of Lytton also blame rail companies for starting the fire that burned that village in 2021, though investigators could find no concrete link between rail activity and the inferno.

And the province also has a campaign to educate energy companies how they can reduce the likelihood that they spark a major fire.

Agricultural

The largest single source of human-caused wildfires are backyard intentional burns gone wrong, BC’s Director of Wildfire told reporters last month. Cliff Chapman said these involve incidents where people are wielding fire as a tool (often to burn fields, yard waste, or garbage) and the flames get away from their users.

Chapman’s statement is the closest we have to a statistical breakdown of human-caused fire types. But even it can mislead. It’s also unclear how many serious fires such backyard burns are responsible for in BC, given such burning tends to occur in the spring and fall, when few wildfires do significant damage.

But one thing is clear: generally the larger the fire you deliberately start, the better the chance that it ends up growing out of your control.

The climate question

The arrival of wildfire smoke in places that haven’t previously experienced such conditions has triggered conspiracies that arsonists are starting fires for political reasons, along with debates about whether and when climate change should be described as a fire cause.

The arson conspiracies are mostly groundless. Every year, some wildfires have been deliberately set. But there’s nothing new in that, and those blazes tend to be a very small proportion of all wildfires. There is also no indication that arsons are on the rise in any way or responsible for the largest fires.

In Canada, arsonists are almost never to blame for the most-serious fires, which tend to be sparked in remote areas either by accident or by lightning. (Although some have recklessly speculated the 2021 Lytton fire was caused by church-burning arsonists, a 2022 report—or any familiarity of the town, direction of wind, location of churches, and burn patterns—reveals the illogic of the speculation.)

Flannigan said arson ignitions in Canada comprise between 1% and 3% of fire starts. When arson does cause fires, it’s often in urban areas—like several that broke out last year in Mission—where they are quickly extinguished before they can grow too large.

The discussion about climate change is more nuanced. But it’s important to distinguish between the ignition of a fire and its spread.

A wildfire begins with an igniting event of some sort. In Canada, when officials discuss the “cause” of a fire, they generally are specifying what ignition event caused flames to begin spreading.

Climate change can play a role in that process—it can influence the development of thunderstorms and the susceptibility of vegetation to catch fire. But blaming individual ignitions directly on climate change is inevitably difficult—and maybe pointless. So when officials say 40% of the fires in BC are caused by humans, they’re referring to the fire’s ignition.

The eventual size of that fire is another matter entirely, and less debatable. Climate change may not directly spark a fire, but it can clearly influence how hot it burns, how quickly it spreads, and its impact on humans near and far. The basics are not particularly complicated: increased temperatures and longer and hotter heat spells dry out plants—the fuel for a fire—and make them more susceptible to burning. (The same pattern is the reason why, even during hot spells, wildfires tend to become most active in the late afternoon.)

One study estimated that human-caused climate change contributed to as much as 90% of the fire area burned in BC in 2017.

It’s clear that the intensity and frequency of heat waves is increasing, as is the length and warmth of BC’s summers.

Studies have found that the number of extremely hot days is increasing. That is leading to more days when fires can grow rapidly, consume huge amounts of forest, and emit billowing clouds of smoke. Temperatures at night—when fires would generally mellow allowing for suppression crews to try to get an upper hand—are also rising.

“Fire is all about the extremes,” Flannigan said. “Three per cent of the fire burns 97% of the area, and much of this happens on a few critical days of extreme fire weather.”

So even as the sheer number of wildfires holds steady or decreases, the amount of area burned has been rising significantly both in BC and elsewhere.

Since humans have caused the climate to change (not to mention created BC’s forest management strategy), it’s not wrong to declare that BC’s wildfire situation, if not the origin of individual fires, is to some degree caused by humans.

But differentiating between human-caused ignitions and human-caused fire growth is also important for those seeking ways to limit both. Declaring that every fire is the result of human agency can emphasize the need to tackle climate change and address emissions. At the same time, doing so can muddy discussions about the other ways humans and their governments exert an influence over increasingly regular wildfire crises.

To the birds

The challenge of analyzing—and preventing—human-caused fires is perhaps best exemplified by the power lines that crisscross British Columbia.

One summer day in 2019, a hawk attempted to land on a powerline. A bird can survive such contact so long as it is touching only the line and nothing itself. But if its body also comes in contact with a pole or another line of a different voltage, the electricity can course through the bird, killing it, and sometimes setting it alight.

On that day, the hawk plummeted to the earth, and its red-hot body ignited the surrounding landscape.

We don’t have more information on the location or size of the fire that resulted—BCWS officials say other more-pressing issues limited their ability to provide more details. But we do know the fire was large enough to prompt an investigation that found the bird. And we also know the blaze would have gone into the books as one of that year’s hundreds of fires deemed to be “human-caused.”

BCWS officials say they don’t have records on how frequently power lines and birds combine to start wildfires. But American researchers recently found that contacts between birds and power lines were to blame for dozens of US fires over a four-year period.

We do know that power lines, with or without birds, are a significant source of wildfires in Canada. While data for BC wasn’t provided to The Current, Alberta’s annual wildfire report provides more detailed data that revealed that power lines helped ignite 79 wildfires in the province just last year.

The power line issue is a useful way to understand the complexity of assigning blame for “human-caused” wildfires and the challenges of reducing their prevalence.

“Human-caused” does not have to mean a specific human lit a match or sparked a flame. In BC’s definition, “human-caused” only means that the ignition source of a fire would not have existed were it not for humanity’s presence.

And some of those human-caused fires are harder to not cause than others.

The power lines are a useful case study. Spikes and other deterrents can discourage birds from perching on wires and it’s also possible to build structures to make it safer for birds to perch on poles. But BC has so many power lines running through forests that such improvements are likely financially unfeasible, especially given the relative rarity of bird-power-line fires.

Other sources of power-line-caused fires are more easily preventable. Trees leaning or falling on power lines have sparked blazes in the past. In 2018, the province changed rules to allow it to fine utility companies up to $100,000 if their improper maintenance of nearby trees led to wildfires.

For other economic sources of human-caused fires, like forestry operations, the province uses regulations to dictate when high-risk activities can take place. For recreation sources, the focus is on a combination of education, brow-beating, and restrictions on activities. Residents frequently join in, begging the province to ban campfires or close backcountry activities earlier in the season.

But the focus on ignitions can sometimes distract from the other, more productive things humans can do to prevent wildlfires from growing into raging infernos.

“Too often, ignitions are used by those who want to move the discussion away from fuel management or climate change,” wildfire scientist Thomas Smith recently wrote.

Are ignitions the problem?

Many wildfire scientists think a focus on preventing fires isn’t useful. Indeed, some have argued that wildfire prevention campaigns may be indirectly to blame for the current fire problems.

Wildfire experts like Bob Gray say the main problem isn’t the ignition of fires, but the state of the forests themselves and the conditions that cause them to spread.

Gray and others point to the Smokey The Bear campaign that told people that only they could prevent forest fires. Those programs, they argue, have done relatively little to reduce fire ignitions, while contributing to an idea that fires must be extinguished as quickly as possible. Even where the number of fires have declined, experts now see forests choked with fuel ready to ignite at a moment’s notice. When such forests catch fire, they burn at temperatures (fuelled by warmer days and, especially, nights thanks to climate change) that lead to more dangerous, faster-moving, and smokier blazes.

So increased damage from lightning-caused fires can outstrip any benefits from reducing the number of human-caused blazes.

That’s borne out in statistics released by the BC Wildfire Service and analyzed by The Current . Between 2018 and 2021, four years for which data on fire cause is available for BC’s most-damaging fires, lightning-caused blazes burned much more territory than their human-caused brethren.

Other statistics show that the number of human-caused fires hasn’t risen over the last decade, even as BC has dealt with five of the worst wildfire years in its history. That echoes a 2018 paper that found that since the 1960s, the area burned, number of large fires, and number of lightning-caused fires have all increased in western Canada even while the number of human-caused blazes has remained steady or, in the case of BC, declined.

Early July provided an example. On July 18, BC wildfire officials noted that of 235 new wildfires, only 13 were designated as “human-caused.” For a province with firefighting resources stretched thin, the scarcity of new man-made fires was a relative blessing. More fires would have been a problem. But even with almost no human-caused fires, BC still had a major problem:

This year has seen the most territory burned ever in BC. Yet the proportion of blazes started by humans is well below normal.

Flannigan says preventing new human-caused fires when resources are thin and forests are very dry is worthwhile. Even though most new human-caused fires may be extinguished before they can do much damage, they still consume limited resources and manpower that could otherwise be deployed to protect communities.

But Flannigan would like to see the province be less reactive and more prepared, so that campfire bands and forest closures take place before the province is on fire, not only after fires have broken out across BC and Alberta.

“This spring, there was this major heat event coming. I’m a fire weather forecaster by training and it’s like a freight train coming, we see it coming. That’s when you put your fire bans, that’s when you put in your forest closures, that’s when you call for additional resources. What happens is the freight train hit, Alberta had 100 fires, and then they called the Canadian Insurance and Forest Fire Centre and say ‘Hey we need resources.’”

Rural politicians in the Fraser Valley have also asked the BC government for the right to close backcountry roads in the vicinity of their tinder-dry communities.

A longer-term improvement would be actually reducing the fuel loads in those forests. But although the BC government has spent millions promoting the use of fire and fuel reductions to clear out vegetation, fire experts—and government spending data—suggest it’s yet to put its money and policies where its mouth is.

Read that story in the Fraser Valley Current later this month.