Even the biggest wildfire begins with a single spark, and the next one on Mount Iron will start off small and quiet. A tiny flash, then a wisp of smoke. An extra shimmer, maybe, in the warm air.
Let’s say the Smiths decide to light the brazier on the patio of their Wānaka home one Friday evening after New Year, and sit around it with friends, marshmallows and beers, admiring the last of the sun’s rays play on the flanks of the mountains nearby. They know about the year-round fire ban on Mount Iron and its fringe of subdivisions, but their fire’s contained. There’s no wind. They’re watching it. It’ll be fine.
The coals are low when the Smiths finally turn in. They farewell their friends, poke their beer boxes into the brazier and tip on the dregs of their riggers. They grab the empties and go inside, locking the back door behind them.
But the fire isn’t out, and overnight it smokes gently. On Saturday morning, the Smiths wake early to load up the car with their mountain bikes and gear, then they set off for the day. A nor’wester picks up in the afternoon, and a gust of wind blows a bright, shining ember out of the brazier and into the heart of the tussock surrounding the Smiths’ patio.
It’s been hot—unseasonably hot, but then everything seems unseasonable these days—and there’s been much less rain this spring and summer, and indeed in the past few years. The landscaper didn’t think about flammability when he planned the garden, and the Smiths have also let it go a bit, with dead vegetation, overgrown trees and shrubs creeping close to the house. The ground has dried out, and the tussock is as flammable as old newspaper.
Another gust blows through the brazier and sends a gently burning shred of cardboard into the tussock. It doesn’t light immediately; a fire needs heat, oxygen and fuel to get going, and the spark has to warm the air around it by a few degrees, then a few degrees more, gently drying out and heating the clumped strands—until, with a tiny flare, it ignites.
The small fire spreads to more tussocks, then to some dried tī kōuka leaves, and then flames shoot up the tree’s trunk and kindle the mingimingi, akeake and banksia, and the heavy skirt of dead fronds hanging on a nearby tree fern. Soon, the garden is ablaze. It’s taken just a few minutes, and no one has noticed a thing. The fire sweeps along the dried-out grass next to the woodshed, in front of the fence.
It’s a typical summer weekend. Mount Iron is one of Wānaka’s most popular recreational areas, and walkers, runners, tourists and families are surging up and down its tracks, stopping at the top to admire the billion-dollar views of mountain ranges across the lake.
Far below, the pine cones in the Smiths’ woodshed have caught, and soon the shed is engulfed in flames. They flick up the fence and across next door’s lawn. From there, the fire ignites a sheet of dusty grass at the base of Mount Iron and races towards a patch of kānuka, one of the most explosively flammable plants in New Zealand, and which covers the mountain’s flanks.
In the house next door, a man smells smoke. Looking out of the window, he sees flames and calls 111, then dashes outside to hose down his lawn, shouting to his neighbours. He hasn’t turned on the tap, so he has to run back. The water pressure isn’t strong enough to make any difference to the fire. Gusts of wind continue to fan the flames, sending them rippling across the grass; they almost enclose the man on his dry lawn and burn on towards his house. The paintwork starts blistering, tiny devils of embers are flying everywhere, and the heat of the flames is like the inside of an oven. The man panics, runs inside and grabs the kitchen fire extinguisher, but it’s a powder one, and only fans the flames further. He gives up. He grabs the kids, the dog and his laptop, fires off a text to the street’s group chat, then runs next door to alert his neighbours.
As soon as Fire and Emergency New Zealand (FENZ) hears of the blaze, an emergency cellphone message is sent to members of the Mount Iron community. One neighbour wants to stay and defend her property; she’s planned her garden with fire risk in mind. There’s a 20-metre space around the house that she keeps clear of vegetation and dead plant matter, with bush sprinklers installed and fire-retardant plants in the rest of the garden. She hoses down her wood pile, turns on the sprinklers, stuffs a tennis ball in a sock into the bottom of the downpipes and fills the gutters.
Because of Mount Iron’s steep slope, because there’s no road up it for fire engines, because of the kānuka, because so many people live nearby, because there’s no water, because it’s a popular spot, because it’s exposed to prevailing nor’westers, because locals and tourists alike can be idiots with cigarette butts and campfires—because of all this, Mount Iron is a well-known high-risk Red Zone, and FENZ brings out the big guns immediately. When firefighters attend a call, they send what’s known as a first alarm: two fire engines. If they get there and need more help, they’ll call in a second alarm, which doubles the number of firefighters. But Mount Iron is so high-risk that the second alarm isn’t more trucks and people—it’s six helicopters.
Meanwhile, the kānuka scrub has erupted. Mānuka and kānuka both burn at a high intensity. Their branches and the ground beneath are full of dead, peeling bark and wood that’s as dry as kindling. The fire crackles and snaps, and smoke pours forth. As the trees torch, the fire whooshes and roars.
Rapidly rising hot air creates a vacuum and pulls in cooler air from around it, meaning the fire creates its own chaotic wind. It blows tiny embers ahead of it, and they leap onto the trees in its path.
Fire burns faster uphill because it can easily reach more unburned fuel in front; radiant heat and smoke also preheat everything in front of the fire, making the fuel even more flammable.
For every 10-degree increase in the angle of a slope, the fire doubles its speed, and when a fire’s speed increases, it becomes even hotter. The sides of wedge-shaped Mount Iron, which sits on the land like a doorstop, are extremely steep. Just 40 minutes after the wind blew the ashes out of the Smiths’ brazier, the blaze has burned up the mountain, wrapped around its sides, and is licking at its top.
It’s also entered the network of subdivisions built on the side of the hill. A few houses have sprinkler systems and low-flammability cladding, but others are clad in beautiful Western red cedar, with kānuka growing close by. The flurry of embers blown ahead of the fire land like snowflakes, setting dried debris alight. (A fire doesn’t actually have to reach houses to burn them—in 2003, a bushfire near a Canberra suburb destroyed 250 homes with flying embers, despite there being a gap of up to 150 metres between the houses and the forest.) As the intense heat surges closer, windows begin to pop.
Up on Mount Iron’s summit, the wind has pushed the smoke towards the top, and it’s choking and disorienting the people still up there. People do different things in wildfires, depending on how much they know. Some smell the smoke and try to sprint downhill, either along the steeper track on the Albert Town side or back down the main track on the Wānaka side—but whichever route they choose, they meet unbearable heat driving up.
Some call 111. Some clamber over the safety rails at the summit and try to climb down the steep cliffs that overlook the main road into Wānaka. Others are reassuring each other. Someone will come. Someone will have called the helicopters.
The helicopters take half an hour to get ready, get water and get there. There’s no road for firefighters to drive to the top of Mount Iron, but they wouldn’t do so anyway—it’s too unsafe. As the choppers finally near the fire, buckets swinging with lake water, one of the pilots spots a drone. Then another. Some people have sent drones up to capture the excitement, and the helicopters are forced to wheel away. The pilots can’t take off again or get closer until the drones are grounded, but the operators are unknown, scattered across the town’s backyards and already anticipating the wows and likes and shares their footage will get on social media.
A handful of people are still at the summit. The flames cut across the walking tracks and burn steadily towards them.
Meanwhile, volunteer fire crews from Luggate, Hāwea and Queenstown are racing towards Wānaka, and two fire engines scream past the Smiths, now on their way home from the day’s biking, empty coffee cups in the console, pastries in a greasy paper bag on the dashboard. Peering ahead, they see thick grey smoke rising and the lick of deadly orange flame, and one of them remembers, with a flutter of horror, that they had the brazier burning last night.
Though this story is a dramatisation, a fire on Mount Iron is one of the scenarios that Central Otago’s firefighting services are preparing for, and many of this story’s elements have taken place in real fires. Recently, a Central Otago grass fire was started by a backyard brazier shaped like the letter C. Its owners didn’t put it out properly one night, and in the morning, they got up and went for a bike ride. While they were out, the wind blew hot ashes straight into the tussock planted around their house. Up it went.
Strong winds and hot embers from another abandoned brazier were responsible for destroying Wellington’s beloved Tapu Te Ranga Marae in winter 2019, razing it to the ground. And another fire started in Central Otago recently when a homeowner stuck a bundle of cardboard in her outdoor fireplace; burning pieces funnelled straight out of the chimney and into the tussock.
Drones have grounded helicopters all over the country, including during the Nelson fires in 2019 and Christchurch’s Port Hills fires in 2017. Each time, the drones stopped firefighting helicopters for several hours, just when they were most needed.
The owner of much of Mount Iron, developer Lynden Cleugh of Allenby Farms Ltd, says the community has been scared of a big fire for years—and disaster came close just after New Year in 2012 when a wildfire broke out on the lower slopes an hour before dawn, burning very close to the Cleughs’ own house. It was the fourth blaze in four days in the Upper Clutha, and tore through tinder-dry scrub with such speed that other residents thought their houses were surely gone.
The fire, which had been set off by a power line arcing in strong nor’westers, travelled so fast it sent some panicked residents running from their homes and out into the wind, banging on each other’s doors in alarm. They packed pets, children, medication, passports, photos and laptops into their cars, hosed down woodpiles, turned on garden sprinklers and raced off.
Extinguishing the fire involved many of the district’s firefighting resources. Some property owners described afterwards how the fire had burned within metres of their houses. A resident of Bevan Place, Mary-Lou Roulston, told reporters at the time that it was “absolutely terrifying” and reinforced how unprepared people were for emergencies.
“When you are at your kitchen window and see flames leaping over the fence, all you can think of is those poor people in Australia,” she said. “You start to look around the house at things you want to take and you have no idea… It is just immense panic.”
One day in March, before COVID-19 restrictions hit, I walk with a flock of energetic locals to the summit of Mount Iron to catch a sunrise. The 240-metre-high rocky knoll is just two kilometres from Wānaka’s town centre, and you only need to look at fitness app Strava to see it’s the most popular track in town.
The views alone must make it one of the best urban walks in the world—the lake glinting before folded layers of sharp blue-grey mountains iced with snow even in late summer, and 360-degree views of Central Otago’s wide, dry plains. Who wouldn’t want to live near this?
I descend the eastern side of the loop track, overlooking where Wānaka is joining up with nearby Albert Town. It’s a sea of new, tasteful dark-grey roofs, sequestered in groves of kānuka. At the base, I stop to gaze up at the scrubby cliffs, and a woman walking her dog calls out to me; I’ve dropped my EFTPOS card. I tell her I’m writing about wildfire risk, and ask what she thinks about it as a local.
“Oh, that’s all on the other side,” she says. “Not here.” She walks off.
“It is not on one side,” says Central Otago deputy principal rural fire officer Mark Mawhinney, when I meet him later that day. “It’s the whole damn hillside.”
A lot of people have their heads in the sand about risk, he says. At a recent community fire meeting, he tells me, one woman said, “I don’t want to know anything about it. Just don’t tell me.”
Mawhinney drives me up into a subdivision on the side of Mount Iron. At the top of the narrow road, a large house is under construction, with a swimming pool that will double as a firefighting water source.
“With many of the houses on the hill, in the worst-case scenario, if you’re stuck there, you’re not going to survive it,” he says, as we stand on the kānuka-clad street in the bright sunshine and look to the north, where the wind will come from. “And that’s our scary scenario. So within 40 minutes the fire has established and it is running through this community. And there will be nothing we can do to stop it.”
In January, New Zealanders watched in horror as Australians fled the worst wildfires in their nation’s history. Though the sunburned country and its indigenous people, plants and animals evolved in a fire-hardened landscape, this year’s fires weren’t normal. In the future, fires may never be “normal” again.
New Zealanders are even less prepared. We’re not used to seeing extreme fires on our long, skinny, relatively damp isles, buffeted by sea breezes. But fires are expected to become more intense and common as our planet undergoes climate change. Soon, we’ll have to get used to them.
“Normal” wildfires burn through undergrowth and scorch trunks, but can usually be managed with time and firefighting resources. Extreme fires are different. They whip up flames so intense that they burn into and through the tree canopy, and can quickly overwhelm firefighters, many of whom are volunteers, particularly in rural areas.
Flames tower into the air and behave unpredictably, throwing embers hundreds of metres, burning fiercely even downhill, leaping across valleys, trapping firefighters. Extreme fires can be so powerful and wide-ranging that they even create their own weather systems.
The Nelson fires of 2019 and the Port Hills fire of 2017 were extreme—some of the biggest infernos seen in New Zealand this century. Extinguishing the Port Hills fire took 66 days, 14 helicopters, three fixed-wing planes, and hundreds of firefighters and members of the Defence Force. It burned 1660 hectares, forced the evacuation of 1400 people from 450 households, destroyed nine house and damaged five—the biggest loss of people’s homes to fire in 100 years. A helicopter pilot was killed fighting the blaze.
One expert described that fire—which actually began as two fires several kilometres apart that then merged into one—as so massive it released the energy equivalent of two to three atomic bombs. Huge pyrocumulus clouds built up above it—a type of cloud created by intense heat that can then go on to cause lightning strikes—and veteran helicopter pilots reported seeing not just the worst blaze they’d ever fought, but also an extremely rare fire tornado. While fire whirls are relatively common—tall, thin columns of whipping flame—a “firenado” is a true tornado, created by hot and cool air intermingling. This one, reported to be 100 metres high and 20 metres wide at its base, may be the first ever recorded in the South Island.
New Zealand hasn’t traditionally seen these sorts of fires. But that’s starting to change. Scientists from crown research institute Scion say more extreme fires are expected here with climate change, and the number of days of extreme fire risk will increase—weather that’s hot and windy, with low humidity. The areas affected will spread from east coast regions that are often dry into places like the Manawatū, Wairarapa and coastal Otago. Blazes like the Nelson or Port Hills fires could become a summer norm.
And fires are expensive. Every year, about 3000 wildfires burn through some 6000 hectares of New Zealand, costing us more than $100 million in damage to infrastructure and public property—although that doesn’t include the cost of damage to rural and conservation land, private property and life. The Port Hills fire cost $7.9 million to stop, and insurers paid out at least $17.7 million in claims.
If more extreme fires are on their way, how can we predict when they’ll happen, where they’ll start and how they’ll spread? An international effort to better understand this is under way at Scion. In early March, Scion’s rural fire research team, together with the Department of Conservation (DOC) and FENZ, ran a series of experimental burns in Canterbury’s Rakaia Gorge. Not many countries can run such real-world experiments, but Scion and FENZ have built up a good relationship over the years, which means the work attracts global interest. (The project is a collaboration with the United States Forest Service’s Missoula Fire Sciences Laboratory in Montana, San José State University in California, and the University of Canterbury.)
The burns, across six four-hectare blocks of mature riverside gorse between one and two metres high, were the second phase of experiments to try to map new wildfire models. The project tested a new burn theory called convective fire spread, which was first put forward by the Forest Service based on lab experiments. Tests were further conducted on Canterbury crop stubble in 2018 and 2019. More complex vegetation such as wilding pines is next on the list.
The researchers are trying to find out how hot and cool air interact during a fire. As fire-heated air rises, it’s replaced by colder air sweeping in from behind—but does this play a bigger part in pushing flames forward than we realise? This movement of air creates a series of peaks and troughs within the flame front. Flames peak in areas where the air is rising, pulling the flame upward, then the fire dips again when cool air flows in.
The current understanding is that fires move forward because of heat radiation from the burning fire front, so fire-behaviour modelling could be improved if the new theory proves true. By the end of this year, the team hope they will be ready to test a new fire-spread prediction model that could eventually mean more accurate information on how often fires will occur, how they’ll spread, whether they’ll turn extreme, and how they’ll behave based on fuel type, topography and a host of other factors.
The March burns were as close to real-life conditions as possible, and were some of the most heavily monitored test fires ever conducted. The site was stocked with a range of instruments—including 30-metre-tall towers topped with sensors, drones flying above to track the fires’ progress, and infrared cameras—to track smoke, weather, atmospheric turbulence, and fire spread and dynamics.
Gorse burns hot; it may be New Zealand’s most flammable plant (see sidebar). Even so, researchers were surprised by the intensity of the fires, which breached the upper limit of some of the instruments and, in the centre, reached almost 1500°C—more than enough to reduce a human body to ash. That heat is hard to fathom if you’ve never been closer to anything hotter than your average bonfire or farm burn-off. The test fires were so hot that they melted well-insulated data loggers and specially designed 360-degree fire cameras.
In fact, says Mark Mawhinney, the researchers fired an area of land similar to Mount Iron, in terms of topography and fuel load, and it topped out at 40,000 kilowatts of heat. (A crematorium ranges from 150 to 400 kilowatts.) During a real wildfire, firefighters step down when the intensity reaches 10,000 kilowatts. That’s how very, very hot Mount Iron could get.
Wildfires are not just something that happens out there in the bush. Globally, there’s a trend of wildfires creeping towards urban centres, increasing the risk to life and property. Data shows house losses overall are increasing.
In the future, with the risk of wildfires increasing, we’re likely to see more involvement at the borders of town and country, known as the rural–urban interface (RUI). That’s where people, lifestyle blocks and houses meet forests, fields, bush, orchards and scrub. It’s where many New Zealanders like to live now, and where development is happening apace as former pastoral land turns into homes. But it’s also a place of high wildfire risk, because rural wildfires can spread into higher-density housing through these RUI suburbs.
“Wildfires don’t stop at the edge of a city, and if they do get into an urban environment, instead of the fuel being vegetation, you’re going to have structure-to-structure fire,” says Scion rural fire research social scientist Lisa Langer. “There is a lot of flammable material within an urban setting.”
Mount Iron and its nearby subdivisions form an RUI area—just like Nelson-Tasman and the Port Hills. Another Scion study is looking at wildfire knowledge in the Mount Iron community in order to help people be better prepared. Recent housing developments have brought new residents and short-term visitors into this area of Wānaka, many of whom lack wildfire awareness and preparedness.
“I suspect quite a lot of the people who have moved into the area are totally oblivious to [the 2012 Mount Iron wildfire],” says Langer.
In the past, social research into wildfire risk has focused mainly on rural areas, small towns and lifestyle properties after wildfires. Not much is known about urban fringe residents’ vulnerabilities, perceptions and behaviours when it comes to fire. They’re a new, vulnerable group, but there’s a gap in knowledge when it comes to how effective various wildfire education strategies have been. Local government planning for wildfire risk in these new developments has also not necessarily kept up with the
Langer says Mount Iron subdivisions are a good example of those urban-fringe communities that are at risk. As of the 2018 census, the area the researchers will study contains approximately 1101 usually occupied dwellings and 228 usually unoccupied dwellings. Non-residents are a complicating factor. Having a more transient community in holiday areas such as Wānaka and Queenstown can exacerbate fire risk because temporary occupiers are disconnected from the local community, and visitors may be more carefree with braziers and cigarette butts than locals are.
Subdivision planning regulation is another issue. Langer says that’s still catching up with wildfire risk, and councils aren’t necessarily preventing high-risk developments. “In this study we also want to start looking more closely at planning—why are we repeating these mistakes of new subdivisions going into risky environments?” she says. “That is something that we will take as far as we can in the study.
“There are some major issues and it’s something that’s repeating itself around the country as new subdivisions are built. The real element for us is having communities that are not aware of the wildfire risk. Real estate agents don’t say, ‘This is a tricky place to live. It’s bit risky.’ You don’t get that kind of cooperation from someone who’s got dollars at stake.”
Development is a source of income for councils, which process and charge for the related consents, as much as it is for the communities who vote for them. Yet it’s the responsibility of those same authorities to carefully weigh wildfire risk and to block development where necessary. In such a system, the incentives are to overlook distant, inchoate danger.
If you talk to people about Mount Iron’s wildfire risk, the first thing that comes up is the area’s kānuka; the hardy, sweet-smelling tree covering the slopes is also one of our most flammable plants. A major issue for Mount Iron landowners is the need to balance development, biodiversity and aesthetics. Although kānuka and mānuka are a major wildfire hazard, people still buy and build in the area because they like its alpine charm.
There are also legislative barriers to the kānuka’s removal. Landowners in the subdivisions on the side of the mountain must retain 40 per cent of the kānuka on their property, a notice set down when the subdivision was built in 2004. (The area was zoned residential in 1998.) Removing more kānuka requires a resource consent. In fact, Allenby Farms Ltd, the long-time owner of much of Mount Iron, was fined $20,000 and ordered to carry out $100,000 worth of replanting after admitting to unlawfully clearing 910 square metres of kānuka in 2016, in what it said was a misunderstanding when clearing land for fire breaks, stock access and preparing to replace fencing.
In 2018, DOC classified kānuka and mānuka as threatened due to the risk posed to them by the disease myrtle rust. The status affords the species extra protection.
“That makes life more interesting, shall we say,” says Erin Stagg, a Queenstown Lakes District Council senior planner.
Stagg says wildfire risk is “a very serious consideration” during subdivision approval. There is provision under section 106 of the Resource Management Act to consider natural hazards, and councils have discretion to decline a subdivision proposal, while developers have to work with FENZ to agree to a wildfire plan.
“I certainly haven’t granted anything in the five years I’ve been here without at least a 10-metre clearance around things and making sure FENZ can get to the house,” Stagg says. “Certainly, if you come in for a subdivision and say, ‘We’re going to screen this with kānuka’, we say no.” Yes, it makes a fantastic screening plant—“until it burns down and burns your house down”, she adds. “It’s definitely front of mind for us.”
There’s also been more of an understanding of rural–urban wildfire risk in the past decade, according to Stagg. When it comes to expansion or redevelopment of existing homes on Mount Iron, she says the council takes a pragmatic approach to kānuka.
“The approach is now, ‘okay, let’s keep the house damp enough to get the people out’, versus your usual fire approach, which would be, ‘let’s try to save the house’. It’s accepting that house is going to be goneburgers [in a wildfire].”
Today, considering the wildfire risk, the special character of Mount Iron and those nationally threatened plant species, some of the existing subdivisions probably wouldn’t be built. Stagg went back and looked at the subdivisions’ original plans, and wildfire risk didn’t seem to have been taken into account during zoning and subdivision.
“I tried to dig it up and as far as I could tell it wasn’t really looked at back in 2004 when that was originally subdivided,” she says. “I don’t know why. But we certainly wouldn’t be zoning [for residential development], and we probably wouldn’t be granting subdivision in that sort of situation today.”
Humans are very good at compartmentalising threats. We are great at banding together in a disaster, at attacking sudden danger in the heat of the moment, but not so motivated to adapt our day-to-day practices for distant risks.
The same is true for our structures of governance, which aren’t incentivised to make sacrifices in the present to reduce intangible risks in the far-off future.
Yet reducing the danger of wildfires requires the participation of everyone involved. Not just to waken neighbours when we smell smoke, but to protect each other in the first place. One neighbour might be scrupulous about clearing their gutters of dead leaves and planting low-flammability shrubs, but the landlord next door might let the grass get away and the house become crowded by vegetation. Squashing the risk requires everyone working together—government, developers, community groups, visitors, neighbours, and that one family with a brazier.