Port Hills fire: How it moved video

AARON WOOD/STUFF.CO.NZ

How the fire has spread and the size of the area engulfed by it.

It looked like the worst was over. But then the wind changed, two fires became one, and the flames spread on the wind and spiralled out of control.

The Port Hills fire is not just notable for its size, but also the combination of factors that fuelled it.

By 10am on Wednesday, the two fires covered around 1000 hectares. The largest spread from Early Valley Rd near Halswell to Cass Peak, while the smaller fire burned in a circle on Marleys Hill.

The fire as it began to cross Dyers Pass road into Victoria Park on Wednesday night.

The fire as it began to cross Dyers Pass road into Victoria Park on Wednesday night.

Less than 24 hours later, the fires had merged, more than doubled in size, and ventured over the hill and down gullies towards Governors Bay.

It had moved rapidly towards Kennedys Bush, and filled into spaces near Kennedys Reserve and Sign of the Bellbird.

READ MORE:
Live: Christchurch fires edge closer
Fires: What you need to know
Brownlee slams belated response
Governors Bay Bush destroyed
In Pictures: Choppers battle blaze
Smoke pollution 'as bad as Asia'
Fires reach Victoria Park
Wildfires visible from space


The fire's quick evolution was due, in large part, to where it was happening: an environment with plenty of ammunition for a fire burning out of control.

"The weather was against us and the fuels were against us," said Dr Tara Strong, rural fire team research leader at Scion research.

"On top of that, the Port Hills themselves create almost their own wind conditions . . . the wind can swirl around the hills and the terrain is changing the wind and the weather as well.

"All of these combine together to create a very dynamic and fast-changing situation. It was at times hard to keep up."

Different fuel types on the Port Hills made the fire hard to predict.
DAVID WALKER/FAIRFAX NZ

Different fuel types on the Port Hills made the fire hard to predict.

The fuels, in this case, refer to vegetation. The hills are dominated by gorse, bracken, grass and pine forests. All highly flammable, particularly in dry conditions. 

The fire's movement changed as it moved through the different fuel types, making it erratic and hard to predict, Strong said.

When day turned to night, lower temperatures prompted an unusual, and dangerous, fire behaviour.

Fire fighters have battled with unhelpful weather conditions throughout the week.
REUTERS

Fire fighters have battled with unhelpful weather conditions throughout the week.

Fire typically moves faster uphill, as the rising warmth preheats the fuel ahead. Firefighters often have better luck containing a fire when it moves downhill.

Ad Feedback

But when night fell on Tuesday and Wednesday, cold air seeped down the valley, bringing the flames along with it.

"In general, it's unusual for a fire to do that," Strong said.

The two fires combined and more than doubled in size over night on Wednesday, threatening homes in the Port Hills.
DAVID WALKER/FAIRFAX NZ

The two fires combined and more than doubled in size over night on Wednesday, threatening homes in the Port Hills.

"That was definitely a risk in this case. Then we had the wind-shift which actually pushed the fire downhill. 

"We also had drier, warmer nights than usual. We didn't get the higher humidity mornings which usually help."

The fire is officially classed as an "extreme fire", which are rare in New Zealand.

  • AREA OF FIRE
  • WHERE THE FIRES BEGAN
  • EVACUATION AREAS
  • CLOSED ROADS AND AREAS
  • AT-RISK AREA

Click on the features for more information.

Overseas, the strategy for large fires is to contain, but in a narrow country where assets are close together, the strategy is to attack, Strong said.

"In general we can't afford to contain and let burn. It's economically not feasible because our space is narrow. It's either going to run into people or a livelihood very quickly.

"So in general it's a direct attack, and attempts to do that on this fire were made, but it wasn't working. So it was quickly switched to protection of property."

Hotspots could be expected for several weeks, she said. Forecast rain would be a huge help.

 - Stuff

Comments

Ad Feedback
special offers
Auckland

House fire in Warkworth

Fire fighters are battling a blaze at a rural house near Warkworth, north of Auckland.

Occupants of the burning house - in an isolated area - have fled and are safe.

Fatal Northland crash

The crash occurred on Kapiro Road, north of Kerikeri.

A crash involving a car and a motorbike in Kerikeri has left one person dead.

'Phantom' to remain jailed

Loizos Michaels, pictured before being sent to prison. He has been decline parole twice.

A conman who calls himself 'The Phantom' and once duped Jonah Lomu has been denied parole.

Thousands gather in Auckland

The Anzac service at the Auckland War Memorial on Anzac Day 2017.

A crisp, clear morning greeted thousands of Aucklanders at the War Memorial Museum Anzac Day service.

Wellington

Services draws thousands video

Willie Apiata greets a soldier with a hongi during the Anzac Day National Commemoration Service at Pukeahu National War ...

Thousands stood in silence in remembrance of those who have fought under the Anzac banner.

Missing hunter found

Search and rescue operation on Mt Taranaki.

A search team airlifted the 62-year-old man unharmed from the Kaweka Ranges.

Crook denied parole 

Kelly Leigh Crook was jailed for her role in the murder of Matt Stevens, which she helped attempt to cover up by faking ...

Kelly Leigh Crook lured a man to a deadly ambush then attempted to cover up murder by faking a car crash scene.

Protest mars service video

Newshub was interviewing peace activists Ellie Clayton and Laura Drew when they were interrupted by David Broome, and ...

"Do it tomorrow, do it the day before - but today is wrong, wrong, wrong." Father and son clash with peace activists.

Canterbury

Wreath behind locked gates video

Jim Lilley, left, Allan Luchford and Cathy Luchford lay their poppies at the Christchurch Citizens' War Memorial.

The Christchurch Citizens' War Memorial has been off limits for six years. But this Anzac Day is different.

Climbers' bodies found

The bodies were found in the Darren Mountains.

The bodies two missing people have been recovered in Fiordland.

River surges to life

Sarah McCall and her family stand on the banks of the Eyre River, normally a dry riverbed, which surged to life on Good ...

"I don't know how it's doing that; I think someone's filling it up," 6-year-old Ruby McCall suggests.

Rentals smelly, musty and mouldy

Rental homes are more than twice as likely to have poorly maintained features than owner-occupied buildings, according ...

Rental homes are twice as likely to smell musty, and three times more likely to feel damp.

Waikato

'Today means everything to me'

The Anzac dawn service attracted thousands to Hamilton's Memorial Park.

It's the one day the world remembers yet every day reminds this family of the price of war.

Body found in bush

Thames

A hunter alerted police to the grim find just after 1pm on Anzac Day.

Five hurt in highway crash

Emergency services are at the scene (file photo).

Two people suffered moderate injuries - three others got away with scrapes and bruises.

Stolen war medals come home

Sam Healy and daughter Jorji, 9, are reunited with their family's war medals.

A year ago thieves stole Sam Healy's grandfather's war medals. On Anzac Day eve, she got them back.

Taranaki

Teen to take on snooker's best

New Plymouth's Mario Hildred, 16, in preparing to take on the world's best in China later this year.

"Obviously I feel a lot of pressure when I get a high break to keep going to get more."

Anzac Day in Waitara

The Anzac Day Parade in Waitara before the civic service.

The weather was perfect for the Anzac Day services held around the mountain on Tuesday.

Missing Taranaki man

Jared Shaun McLean has not been heard from since Saturday.

"We all are actually worried, it's just unlike him to do this."

Bramhill for Greens

Dr Stuart Jeanne Bramhall has been picked as the Green Party's candidate for the New Plymouth electorate in the 2017 ...

Long time environmental activist Stuart Bramhill is the Green's candidate for New Plymouth. 

Manawatu

Gorge could be closed for weeks

About 3,500 cubic metres of earth is blocking the Woodville end of State Highway 3 through the Manawatu Gorge.

Manawatu Gorge set for another long closure after two slips block lanes.

Woman badly hurt

Police are at the scene of a crash in Dannevirke, where a motorcycle hit an elderly woman.

An elderly woman is in a critical condition after being hit by a motorcycle in Dannevirke.

Child basher in denial

Peter Ross Moran wants to live near a child whose brain he damaged.

He caused his victim's brain to become "watery mush", but still denies doing anything wrong.

Smoke and coffee to start the day video

Vietnam War vet Alby Armstrong gets ready for the dawn service in Palmerston North.

Alby Armstrong thinks about other soldiers when he's at a dawn service.

Nelson

Richmond remembers lost heroes

Poppy laying during the Anzac Day service at War Memorial Gardens, Richmond.

Anzac Day crowds overflowed into the streets around Richmond's memorial gardens.

A city pays tribute video

Anzac Day dawn parade and service at Anzac Memorial Park, Nelson.

Thousands woke before dawn to attend Anzac Day dawn service in Nelson.

Nelson: The new Silicon Valley?

Markus Erdmann and Vivian Escorsin are part of the entrepreneur group Local.Foundation who are organising a business ...

Business group says Nelson has potential to become "start-up hub of New Zealand".

Flowers revive wartime memories

World War II veteran Allan Carson holds poppies from Flanders Fields in Belgium, brought back from a visit there in ...

A Nelson man's souvenir from a WW1 battlefield stirs up two generations of memories.

Marlborough

Pak 'n Save's unusual policy

Two German men have stolen meat, cheese, beer and herbs from Pak 'n Save Blenheim.

What to do with food found on a shoplifter's person? Put it back on the shelves, of course.

Anzac day treats

Kaikoura council earthquake recovery economic lead Mel Skinner with a plate of Anzac cookies from Wellington's Good ...

The Good Bitches' homebaking brings a sweet reassuring note to earthquake recovery effort.

'It's a reality check'

Dawn services at the Seddon Memorial Hall.

Friends, family remember those who made the ultimate sacrifice in Anzac commemoration.

'The supreme sacrifice'

Australian Army veteran Betty Binnie gets her two remounted medals pinned to her chest by RAAF Squadron Leader Marcus Watson.

Rocked to the core by earthquakes, the people of Ward stand strong to remember the fallen this Anzac day.

South Canterbury

Honouring sacrifice

War veterans march on Memorial Ave towards the cenotaph at the Anzac Dawn Service in Timaru.

A crowd of a few hundred stood at the cenotaph in Timaru to commemorate Anzac Day.

Raising awareness 

Volunteer firefighter and former NZ Army infantryman  Maaka Mckinney is escorted into Timaru from Waimate by Timaru ...

Maaka McKinney is raising awareness for depression among first responders.

New book on war hero

Tom O'Connor has published a book on Waimate war hero Eric Batchelor.

The life of one of New Zealand's most decorated soldiers has been detailed in new book.

Man killed in crash

A man is dead after a crash on Freehold Creek Bridge at Lake Ohau.

One person has died after a single-vehicle crash on a bridge in the Waitaki District.

Southland

50-year-old receipt returned

Sue Samson with the 50-year-old receipt left in the Winton Night 'n Day store on April 6.

They'd kept their honeymoon receipt for five decades. So when a shopkeeper found it, she knew she had to return it.

'Two shot' in city

Police have cordoned off Otepuni Ave in Invercargill after a suspected double shooting.

Police indicate two people have been shot and one person is in custody following an armed incident in Invercargill.

Kiwi climbers perish in Fiordland

The bodies were found in the Darren Mountains.

The pair were roped together traversing a "climber's Mecca" when a fall cost them their lives.

Nasa balloon seen from Chch

Ashley Marles managed to photography the balloon with his own observatory.

That "bright stationary object" is headed for outer space - with an Anzac poppy in tow.

Ad Feedback