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The ‘catastrophic mega-blaze’ that would have scorched Sydney


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The ‘catastrophic mega-blaze’ that would have scorched Sydney

Updated July 27, 2020 13:18:52 As the first Black Summer inquiry prepares to report,  we reveal the inside story of Australia’s biggest bushfire.It burned for 79 days and remains seared in the memory of all who feared and fought it. The statistics are staggering. Over a million hectares burned; a hundred homes destroyed on Sydney’s…

The ‘catastrophic mega-blaze’ that would have scorched Sydney

Updated

July 27, 2020 13:18:52

As the first Black Summer inquiry prepares to report,  we reveal the inside story of Australia’s biggest bushfire.

It burned for 79 days and remains seared in the memory of all who feared and fought it.

The statistics are staggering. Over a million hectares burned; a hundred homes destroyed on Sydney’s doorstep.

Gospers Mountain became famous as Australia’s first “mega-blaze”.

But behind the smoke, flames and evacuations, there is still much to learn about the monster.

The ABC has pieced together data, imagery and interviews to form a new narrative of the fire.

The NSW Rural Fire Service (RFS) and National Parks and Wildlife Service (NPWS) contributed information and access to operational commanders, some speaking for the first time.

We can reveal the fire’s starting point, and how close Sydney’s suburbs came to disaster.

Firefighters tell of raised hopes as the flames faltered, and despair as backburns backfired.

This is how the mega-blaze unfolded.

Day 1: Ignition

Australia’s largest bushfire almost never happened.

In late October 2019, a violent storm swept across NSW.

By the time it reached the Wollemi National Park north of Sydney, it had almost fizzled out.

In all, the storm unleashed just under 19,100 bolts of lightning.

The ABC has analysed every strike using meteorological data, cross-referenced with records from weather stations across NSW.

We found the lightning that started the mega-blaze was an outlier.

At 10:55am on October 26, strike number 19,068, lasting just 518 milliseconds, fell on the eastern edge of the dying storm.

That lightning bolt hit a stringybark tree deep in the park at Running Stream, 15 kilometres from the nearest road.

NPWS dispatched a helicopter with a Remote Area Firefighting Team (RAFT), but strong winds stopped them winching down.

Months later, a helicopter is still the only way to reach the ignition point.

An ABC team landed at a makeshift helipad, hewn from the bush by another RAFT team.

Police had been there just days earlier, felling stringybarks to take forensic samples for a coronial inquiry.

Today that tree seems almost insignificant — another charred trunk in a devastated forest. But its location was critical.

The Wollemi park’s craggy gullies and shady south-facing slopes would typically form a natural fire barrier.

But not after a decade of below-average rainfall.

“The landscape was extraordinarily dry — we’re looking at probably record dryness within the resolution of our records,” said Professor Ross Bradstock, director of the Centre for Bushfire Risk Management at the University of Wollongong.

Wind gusts of more than 80kph fanned the flames, but as the blaze remained isolated, it was not deemed a priority.

Most remote fires started by lightning strikes are extinguished early.

Only 10 per cent grow beyond 500ha in size.

The first thermal images of the blaze showed it burnt about 65ha in less than two and a half hours after it was ignited.

By the next morning, it had torn through 521ha of land, and had a perimeter of 3km.

“We need to keep in mind that at that point in time there was significant fire activity across the state,” NPWS Blue Mountains director David Crust said.

“Pretty well everywhere from the Queensland border south to the Sydney basin was involved in firefighting.”

Three water-bombing aircraft were sent to try and douse the flames, and six RAFT crews were winched in.

By the mid-afternoon on October 27, hot, windy conditions meant they had to pull out.

Authorities abandoned the possibility the fire could be snuffed out and braced themselves for the possibility of a “campaign fire” — a blaze which can’t be extinguished and presents a constant threat.

Instead of trying to put it out, the strategy became one of containment.

Day 11: The sleeping giant

One of the untold stories of Gospers Mountain is how close the fire came to going out.

It was almost just another statistic, one of more than 11,000 fire “incidents” across the state in NSW’s Black Summer.

As firefighters were preparing for a long campaign against the remote blaze, the weather changed, and rain came down over the fireground.

Although falls totalled just 10 millimetres, “line scans” taken from surveillance aircraft detail the dramatic change.

These high-resolution thermal images are used to plot fire spread.

On this image from November 6, the blaze is barely visible. It was close to being out.

RFS Superintendent Karen Hodges was keeping watch on the blaze, then still under NPWS control.

“We did have some rainfall in the fire ground and the fire went to sleep, so to speak, for a couple of days.

“But as soon as the weather turned again, it reared its head.”

Once its embers were fanned back into life, there would be no stopping the Gospers blaze.

At first it was travelling an average of 700m a day.

But on November 7, it began the first of two extraordinary runs, racing through 12km of bush in a day.

“We could not control the fire the way we wanted to and the way we have in the past,” Superintendent Hodges said.

“Nothing we did stopped it. No matter what we tried, it was just a continuous beast.”

On November 11, acting on advice from RFS Commissioner Shane Fitzsimmons, NSW Premier Gladys Berejiklian declared a week-long State of Emergency.

At that point, the NPWS handed command of Gospers Mountain to the RFS.

Superintendent Hodges, a firefighting veteran of 32 years, now faced the biggest challenge of her career — taming the beast.

Day 17: State of Emergency

On November 12, a “catastrophic” fire warning was issued for Greater Sydney, the Central Coast and other parts of the state.

It was the first time the new rating had been used.

“No matter where you are … everybody has to assume the worst,” the Premier warned.

By that morning, Gospers Mountain had doubled in size again to almost 25,000ha, threatening homes in the small, isolated village of Mellong.

Driven by fearsome winds, the fire made another astonishing run — covering 11.7km in under three hours.

Superintendent Hodges calls it one of the worst days she’s ever seen.

As the fire closed in on Mellong, it developed its own weather system.

That happens when superheated air rising in the smoke plume rapidly expands and cools, eventually generating its own thunderstorm.

The phenomena is called a pyrocumulonimbus, or “pyro”, cloud.

Firefighters describe it as a “black swan” event — named for its rarity.

Local weather stations did not record any lightning from the pyro cloud, but RFS volunteers witnessed strikes starting spot fires to the east.

Superintendent Hodges said she had never seen flames move so fast.

“That’s when I got the indication that this fire wasn’t normal … that’s when I knew that we were probably in for a world of hurt,” she said.

By day’s end the fire had doubled in size to 56,000ha, with a perimeter of 170km.

Craig Burley was the RFS operations officer in the control centre responsible for monitoring the blaze.

“It was a very, very dynamic situation,” he said.

“We were obviously concerned, first and foremost, for the welfare of the firefighters on the ground.

“It was a challenging day, [they] don’t come much tougher.

“You know, a fire will whack you a few days, but we were getting belted day after day.”

Day 31: Admitting ‘defeat’

In late November, Superintendent Hodges and her team settled on a strategy to use the largely dry MacDonald River as a containment line 20km east of the fire front.

If they could stop the blaze from crossing the riverbed, it would be a major victory.

“The strategy in the MacDonald River took us days and days of hard work [and] it was mostly complete,” she said.

It would be for nothing.

By November 24, storm clouds again gathered over the Wollemi.

Meteorological data shows there were 19,016 lightning strikes in the area over the next two days.

Across November 25 and 26, lightning sparked several new blazes beyond the containment line.

The foundations of the mega-blaze were set.

“It was a day of absolute devastation for the people because we realised that what we’d been doing to date was now null and void,” Superintendent Hodges said.

“We had to stop what we were doing and admit defeat.

“The amount of effort that they had put in was all for nothing.”

Day 41-49: Backburns backfire

Using fire to fight fire is a universal tactic.

Backburns create containment lines by robbing a bushfire of fuel, but they require careful planning and favourable winds.

The RFS used them successfully throughout the Gospers Mountain campaign.

But they did not always go to plan.

At about 6:00pm on December 3, Mr Burley received a strange call.

His crews were racing to complete backburns along two established hiking trails to protect homes at Colo Heights, about 40km from Sydney’s north-western outskirts.

But the operation had to be suspended when one of his firefighters found an empty car.

The teams feared whoever left the car would become trapped between the backburn and the fire front.

It was 17 hours before police located the car’s occupants, swimming on inflatable lilos in the Colo River.

By then, the wind had shifted and backburning had to be abandoned.

With containment lines disrupted, the fire charged ahead, and destroyed houses in Colo Heights.

For Mr Burley, it was personal — his wife was forced to evacuate as the fire roared towards their home.

Thankfully, it was saved.

“I’m very confident that if we’d been able … to complete that back-burning operation, we could have held the Gospers Mountain fire section of the fire right there,” Craig said.

“That would have made one heck of a difference to the Colo Heights village.”

Elsewhere, at Mount Wilson, another carefully planned backburn on the southern flank of the fire turned to disaster.

Spot fires were sparked when winds shifted unexpectedly, and the operation got out of control.

That was the start of the Grose Valley fire, the blaze that would go on to destroy dozens of homes around Bilpin, and form part of the mega-blaze.

Firefighters were devastated.

“What happened was no-one’s fault,” Superintendent Hodges said.

“The firefighters that day did their very best to try to contain it. No matter what we tried. They tried their very best.”

Day 38: The mega-blaze is born

By December 5, alarm bells were ringing.

Computer mapping indicated multiple fires were about to join.

“We were always planning for that possibility,” Superintendent Hodges said.

“So we had that in the back of our mind, that one day that might happen.”

What became known as the “mega-blaze” was a combination of six fires.

Several small fires had already been swallowed up when five of the blazes merged on December 6.

The ABC sent the first breaking news alert at 11:29am: Gospers Mountain, the Little L Complex and Three Mile fires had joined.

Later in the day, they would combine with the Paddock Run and Thompsons Creek fires, and after that, merge with another blaze at Kerry Ridge.

By the end of the Black Summer, the Gospers Mountain blaze accounted for half of the mega-blaze at 512,142ha, the Kerry Ridge blaze 323,900ha, the Little L Complex 169,834, the Three Mile fire 45,944ha, and the Grose Valley fire 19,920ha.

“The vastness, the enormity of the area that we covered. It’s over a million hectares in size. It’s a huge area that we had to deal with,” Superintendent Hodges said.

The fire was now so big, surveillance aircraft that normally take one pass to photograph a blaze were having to fly over sections of it six times to map them properly.

Day 56: The battle for Sydney

With catastrophic conditions again forecast for December 21, Premier Berejiklian declared a second State of Emergency.

Thousands of firefighters were now in the field, as strike teams from interstate and overseas joined the battle.

“The first thing you experience is the ember attack,” Mr Burley said.

“It’s like a snowstorm but embers, and then the colour of the sky turns to orange, then dark.

“It’s like sitting in front of an oven.”

Volunteer firefighter Stacey Kent was with her RFS team on the fire’s southern flank, trying to stop it crossing the Hawkesbury River and making a run into Sydney’s northern suburbs.

“Just walls of flame, and like, as far as you could see, from the treetops to the sky was just orange, no matter where you looked,” she said.

“If it crossed the river, it was going to be catastrophic.”

By then, emergency management officials at all levels of government were planning for the worst.

The ABC can reveal extensive preparations were made to evacuate thousands of residents from Sydney’s Hornsby and Hills districts.

Evacuation centres and escape routes were mapped out.

If the fire had broken through, it would have triggered one of Australia’s biggest peacetime evacuations.

Shopping centres and RSL clubs in the Hornsby area were on standby to be used as refuges.

“We were pretty much on a heightened level of alert if I could say that even just emotionally for probably four weeks,” said Steven Head, Hornsby Shire Council’s general manager.

“The day when we had the catastrophic fire risk, you might remember that that day on the 12th of November, that was certainly a day when we all felt completely on edge.”

Fire expert Professor Bradstock estimates the fire could have covered the distance in a day, impacting hundreds of homes on the urban fringe.

Then a southerly wind change blew the flames back from where they came. The containment lines held.

Few knew how close suburban Sydney had come to disaster.

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Day 79: From fire to flood

While December 21 was the peak of the blaze, the fire continued to burn, scorching an astonishing 1,071,740ha of land.

The Gospers Mountain fire alone was the biggest bushfire from a single ignition point in Australian history.

The mega-blaze is among the world’s 10 largest bushfires on record.

Across Christmas and New Year, volunteers worked to deepen defences around the mega-blaze, as attention swung to fires devastating the state’s South Coast.

Gospers Mountain was finally declared contained on January 12, but it still had a surprise in store.

It came in the form of another extreme — flooding eventually extinguished the blaze on February 10.

“When those rains came it was a very, very good feeling,” Superintendent Hodges said.

The NSW Independent Bushfire Inquiry is due to report back this week.

Every professional interviewed for this story fears more extreme weather events will drive similar infernos in future.

“The chances of having a super-sized fire like this are increasing,” Professor Bradstock said.

Superintendent Hodges hopes Australians will ensure their properties and families are better prepared for severe bushfire seasons.

Ms Kent says the community has another important role, too.

“It was absolutely incredible the generosity and support that the public had for the firefighters, and [it] really showed the best of Australian mateship,” she said.

“You don’t realize how much of a difference that the support of the firefighters really gave us to keep pushing and going out there day after day.”

Credits

  • Editor: Riley Stuart
  • Commissioning editor: Mark Davies
  • Photography: Mridula Amin
  • Video: Andrew George, Billy Cooper, Jack Fisher
  • Graphics: Ryan Boyle, Mark Doman
  • Meteorological data provided by: MetraWeather, Bureau of Meteorology, Ventusky, Blitzortung and NASA Worldview
  • Special thanks: Ben Shepherd (RFS), David Crust (NPWS)

Topics:

disasters-and-accidents,

fires,

bushfire,

police,

crime,

law-crime-and-justice,

national-parks,

environment,

bilpin-2758,

sydney-2000,

nsw,

gosford-2250,

newcastle-2300

First posted

July 27, 2020 05:12:54

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