It began on the afternoon of 14 July 2014, as storm clouds gathered over a remote patch of north-central Washington state. They carried no rain, only a crackle of electricity. Lightning ripped through the heavy air, striking the ground and setting the stage for disaster.
Within hours, four separate blazes roared to life. Fanned by hot, relentless wind, the flames soon converged into a single inferno. Washington now had a megafire on its hands, a blaze beyond all normal categorisation.
A towering column of smoke punched 30,000ft (9km) into the sky, scattering embers that rained down to ignite parched grass, brittle trees and bone-dry brush.
By the time it was over, an area the size of Los Angeles lay scorched, with more than 350 homes reduced to ash.
The blaze became known as the Carlton Complex fire – the largest in Washington’s history, surpassing the infamous Yacolt Burn of 1902. But while the previous record had held for more than a century, this one would last barely a year. In 2015, another wave of wildfires swept across the state, laying waste to over 300,000 acres of land.
“When I first started, a mind-boggingly large fire was 10,000 acres,” says Vaughn Cork, a fuels analyst at Washington’s Department of Natural Resources and a wildland firefighter with over 20 years’ experience battling blazes in the state. “Now we don’t even bat an eye at that – it’s not even considered a large fire on the ground until it’s north of 50,000 acres.”
Cork’s experience isn’t unique. Across Washington, the Pacific Northwest and the entire United States, fires are getting bigger, badder, hotter and harder to control. The reasons are far from straightforward; the solutions, even less so.
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America ablaze
The Carlton Complex would once have been considered an exceedingly rare, if not freak, event. Today, it looks less like an outlier and more like part of a disturbing new normal. Across the US, wildfires are growing in frequency, intensity and scale, with impacts spreading far beyond the burn zone.
In the past two decades, the number of wildfires in the US has doubled compared to the late 20th century. In some regions, such as the Great Plains, the increase has been even more dramatic, with four times as many fires as before.
The season itself has also stretched. Peak fire activity, which used to arrive in August, now comes a full month earlier, in July.
But these fires aren’t just more common – they’re fiercer. The fastest-moving blazes in the West today grow around 250 per cent faster than they did at the turn of the millennium, and in California that jumps to 400 per cent. This explosive behaviour makes these blazes almost impossible to contain once they’ve escaped initial suppression efforts.
The scale, too, is staggering. Every one of the ten largest US wildfire seasons on record has happened since 2004. An area the size of five Yellowstone National Parks is routinely burned annually, and those numbers are continuing, on average, to climb.
Whole landscapes are being reshaped. Between 2015 and 2021, wildfires tore through 85 per cent of California’s giant sequoia groves. These are trees that can live for thousands of years, yet in a single season an estimated one in ten of the world’s remaining mature sequoias was lost.
Communities in the line of fire face devastating losses: California’s 2018 Camp Fire alone destroyed nearly 19,000 structures, displaced 50,000 people and caused $12.5 billion in damages. This year’s LA fires dwarf that figure, with damages over $100 billion.
Wildfires, in short, are no longer just a problem for the western US. They are a national crisis – ballooning in size and ferocity just about everywhere you look.
A tale of two fire regimes
You might assume climate change alone explains today’s wildfires. And it’s true, rising heat plays a huge role. But the reality, much like the air during fire season, is a little hazier.
“For there to be a fire, you need two things,” says Dr Olivia Haas, an expert on global fire patterns at the University of Reading. “Enough vegetation to burn, and for that vegetation to be dry enough to ignite.”
Most landscapes, she explains, fall into one of two camps. Some are fuel-limited – dry enough to burn, but with little vegetation to feed the flames. Others are dryness-limited – dense with plant matter to burn, but too wet to catch fire.
Western Washington is a textbook case of a dryness-limited landscape. It’s a lush, steep and fuel-rich temperate rainforest. Historically, fires here have been rare. The region’s ‘fire return interval’ – the average time between major blazes – has typically been measured in centuries.
That doesn’t mean megafires, which are typically defined as any blaze over 100,000 acres, have never happened. The infamous 1902 Yacolt Burn, for instance, was vast even by today’s standards, with over 230,000 acres destroyed. But such events usually required an unusual set of ingredients: prolonged drought in the damp forests, followed by a strong offshore wind from the east.
Normally, Washington’s prevailing winds blow in from the Pacific Ocean, bringing fire-suppressing moist air to the whole northwest US. Easterly winds, meanwhile, have travelled across the landscape of the US, meaning they are much drier.
Meanwhile, climate change is making droughts in the Pacific Northwest more frequent and severe, and heatwaves are happening more often, with greater intensity. When an easterly wind does arrive, the tinderbox conditions are already set.
Not everyone is convinced this means more megafires. Prof Clifford Mass, a meteorologist at the University of Washington, argues that the real driver of megafires in western Washington isn’t temperature but the easterly winds.
His models suggest the winds may actually become less common in a warming climate – which could counteract the risk of megafires.
“You have warming going on, which is good for fires. But that’s small compared to the drop in easterly winds we’d expect under global warming,” Mass says. “The key thing is these winds. That’s everything.”
Meteorologically speaking, Mass may be correct, but others disagree with his conclusion, pointing out that the winds are just the final piece of the puzzle. If droughts stretch longer each year, at some point a strong east wind will arrive to fan the flames. Cue the megafire.
“What we are doing is changing the fire return intervals,” says Michael Medler, a professor of environmental studies at Western Washington University. “If you take a bunch of 500 year fire return interval areas in the West side and turn those into 100 year fire return intervals, you may still not see a fire for a lifetime, but the odds have gone up 500 per cent.”
What this underscores is just how uneven the fingerprints of climate change can be. Its effects on dryness-limited landscapes vary dramatically from place to place.
But the principle remains: in regions where vegetation is plentiful, if warming trends tilt the balance toward drier, more fire-friendly conditions, megafires are almost inevitable. There’s simply too much fuel waiting to burn.
Fueling the Flames
If dryness-limited regions like Washington’s rainforests are tinderboxes waiting for drought, fuel-limited landscapes face a different, somewhat surprising, problem: too little fire.
For much of the 20th century across the US, the tactic when it came to fires was simply to fight them with everything you had. In fact, the Forest Service even adopted a so-called ‘10am policy’, whereby any fire that started should be extinguished by 10am the following day.
The thing is, this policy worked really well. Too well, in fact. What seemed like a sensible reaction to flames ripping through a landscape has resulted in what ecologists now call a ‘fire paradox’ – by stopping small, natural burns, we’ve actually created conditions for much larger, more destructive ones.
As Haas puts it, “What suppression does is alter your background fire regime, because instead of that fire naturally coming through, it now hasn’t occurred. So you get a buildup of fuel that hasn’t burnt due to fire suppression policies over the past 100 years.”
The 10am policy may be gone now, but its effects linger with us to this day. That accumulated fuel means that places that should be fuel-limited, well, aren’t.
Prof Rory Hadden, a fire scientist at the University of Edinburgh, puts it bluntly: “By extinguishing the fires, what it's really done is resulted in an enormous fuel buildup. Now, what an enormous fuel buildup means is you get really, really high fire intensities. And when you get high fire intensities, there's basically nothing you can do to fight the fires.”
In the past, a megafire might have left behind a mosaic of lightly and heavily burned patches. Today, those same-sized fires are far more likely to burn uniformly at high severity, sterilising soils and killing entire stands of trees.
“We’ve changed the patchiness,” Medler says. “Fifty or so years ago, if we had a 100,000-acre fire, far fewer of those acres would have burned so intensely hot that all the trees were killed. Now we’re ending up with 100,000-acre holes where there won’t be proper forest again for hundreds, if not thousands, of years.”
By then, whatever forest does grow back will be of a completely different character from the one that was there before. The forests we know today will, inevitably, be lost forever.
Climate change adds fuel to this fire – literally. Hotter, drier summers prime the overgrown forests for ignition. If these follow years of heavier-than-average rainfall – another consequence of climate change in many places – then a process known as ‘hydroclimate whiplash’ adds an extra abundance of undergrowth.
“The history of fire suppression and fuel buildup as a consequence of that suppression is coinciding with changes in the climate system in a lot of areas,” Haas says. “We’re getting this perfect storm of risk, from both fire policy histories and the changing climate.”
The lesson is ironic at best, tragic at worst: fire itself isn’t the enemy, the absence of fire is.
Living with fire
Whether you live in the lush green forests of the Pacific Northwest or drier, more arid regions like Southern California, megafires are coming to a wildland near you. So far, so terrifying.
But surely, we’re not simply at the mercy of an inferno ready to strike at a moment's notice? And if aggressive fire suppression isn’t the answer, what is?
The challenge is daunting. According to estimates from five federal land management agencies, over 100 million acres of land are now in need of some form of thinning or prescribed burning to reduce fuel loads. To put that in perspective, that’s an area larger than the entire state of California. Treating every acre simply isn’t feasible – both financially and logistically.
And, as Cork points out, the risk is no longer confined to a handful of communities. “Pretty much every urban centre [in Washington] has a certain amount of risks,” he says. “And all across the western United States, there are communities that may not have seen a whole lot of fire due to exceptionally good suppression effectiveness in the past decades that are definitely at risk.”
So where do you start when you can’t do it all? An obvious place is to prioritise people first. That means focusing on forests and wildlands that border towns and suburbs, reducing fuels in the ‘wildland–urban interface’ where lives and property are most vulnerable.
But protecting communities isn’t only about the forests beyond the fence line. You can play a role too. According to the National Fire Protection Association, most houses ignite not from direct flames, but from wind-borne embers, which can travel more than a mile.
Their guidance emphasises the concept of the ‘Home Ignition Zone’, the area within 60m (200ft) of a house.
Key steps you can take to protect your home’s ignition zone include:
- Clearing roofs and gutters of leaves and needles that could catch embers.
- Using fine metal mesh to cover vents and prevent embers from entering attics or under decks.
- Replacing or repairing loose shingles and broken windows.
- Keeping flammable materials like firewood or mulch away from exterior walls.
- Screen or box-in areas below patios and decks with wire mesh to prevent debris and combustible materials from accumulating.
- Thinning and spacing trees, mowing grass short and removing vegetation under trees that allow fire to climb from ground to canopy.
- Create firebreaks with driveways, paths, patios and decks.
In short, resilience begins at the doorstep.
Still, no amount of thinning or home hardening will erase wildfire risk entirely. “Fire is a necessary and natural part of the landscape,” Cork reminds us. “It’s going to happen and the best thing to do is to be prepared for it and take proactive measures.”
And as Medler cautions, unless the world also tackles the root driver of worsening fire weather, there’s a limit to what these strategies can achieve.
“Unless something extraordinarily unexpected happens with the current progress of climate change,” he says, “every decade will be the largest set of fire seasons we've seen – until the next one."
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