Why three giant fires could merge into one 'mega blaze' TODAY on NSW/Victoria ...

Three giant fires could merge and form a 'mega blaze' along the New South Wales-Victoria border as soon as today, fire chiefs have warned, ahead of worsening conditions later this week.

Country Fire Authority State Response Controller Gavin Freeman told the Today show on Tuesday morning there's a 'real potential' the fires could join in the next few hours.

Mr Freeman said fire crews are keeping a close eye on the area today, as the potential blaze could wipe out roughly half a million hectares of land.

In NSW, it's only a matter of time before the Corryong fire connects with the 297,000-hectare Dunns Road fire in the Snowy Mountains.  

Emergency Services Commissioner Andrew Crisp said there's 'every chance' a 'megafire' could start, but pointed out that one large combined blaze isn't necessarily more dangerous than three smaller fires.

'But the mega fire, it is mega in terms of area. Just because you've got a large area, it doesn't mean it's all fire,' he said on Monday.

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Three giant fires could merge and form a 'mega blaze' along the NSW-Victoria border as soon as today

Three giant fires could merge and form a 'mega blaze' along the NSW-Victoria border as soon as today

Country Fire Authority State Response Controller Gavin Freeman told the Today Show on Tuesday morning there's a 'real potential' the fires could join in the next few hours

Country Fire Authority State Response Controller Gavin Freeman told the Today Show on Tuesday morning there's a 'real potential' the fires could join in the next few hours

Three fires spanning two states are threatening to merge into a 'mega-blaze' as authorities repeatedly urge locals to flee. Pictured: A family boards an Australian Army Blackhawk helicopter at Omeo Showgrounds in Victoria

Three fires spanning two states are threatening to merge into a 'mega-blaze' as authorities repeatedly urge locals to flee. Pictured: A family boards an Australian Army Blackhawk helicopter at Omeo Showgrounds in Victoria

'A lot of it is burnt out. That's not such a bad thing. You definitely haven't got active fire on certain edges. It doesn't mean you're going to see 1.5 to 2.2 million hectares of burning bush.' 

Victoria's State Response Controller David Bruce said three fires combining with each other would be 'very concerning'. 

'Obviously we have some conditions on Thursday and Friday which will increase the fire danger ratings and, with the potential of these fires joining up, will create some weather conditions that will be very unpredictable and very challenging to fight,' he said.

Meanwhile, all emergency bushfire warnings in Victoria have been downgraded after rainfall provided some respite, but conditions are expected to deteriorate again on Friday. 

There have been 25 deaths this bushfire season and more than 1,600 homes have been lost, with almost six million hectares across Australia having been burnt, which is about the size of the Republic of Ireland.

Two people remain unaccounted for in NSW, where there has already been 20 fatalities, and Victoria and South Australia have reported two and three deaths respectively.

At least three people were killed on Saturday, while four people missing in Victoria are feared dead. As a fire front approached the town of Batlow (pictured) on Saturday, the sky was filled with orange flames and thick, grey plumes of smoke

At least three people were killed on Saturday, while four people missing in Victoria are feared dead. As a fire front approached the town of Batlow (pictured) on Saturday, the sky was filled with orange flames and thick, grey plumes of smoke 

Firefighters (pictured at Batlow on Saturday) have spent weeks defending lives and property from the blazes

Firefighters (pictured at Batlow on Saturday) have spent weeks defending lives and property from the blazes

Jesse Collins breaks down as she talks about how hard it has been getting water to Cobargo on the NSW south coast

Jesse Collins breaks down as she talks about how hard it has been getting water to Cobargo on the NSW south coast 

There are still 15 'Watch and act' warnings' in Victoria and emergency supplies are being flown into the state's 18 cut-off communities.

There are around 300 people waiting to be evacuated from the coastal town of Mallacoota where aircraft have been grounded by smoke.

South Australia's tourist hotspot Kangaroo Island is one of more than 100 fires still burning across the country. 

The CFS says a large fire continues to burn at Cape Borda, towards the lighthouse, in inaccessible terrain.

On the north coast, there are a number of areas of concern around Snug Cove and Stokes Bay where firefighters have responded to multiple flare-ups.

At Andamel, northwest of Vivonne Bay, there has also been renewed fire activity. 

So far the island fire has burnt more than 155,000 hectares inside a 300-kilometre perimeter with many homes and other buildings feared lost.

Most roads within the fire zone remain closed as work begins to replace key infrastructure.  

In an unprecedented move, almost 500 Army reservists have been called to help in the bushfire response and that number could reach 3000.

A smoke haze sits above Melbourne and Canberra - which recorded the worst air quality of any major city in the world on Monday - and the smoke has even made its way to New Zealand.

Some estimates suggest 500 million animals have died in the fires.

Nothing but a river - about 10kms of space - stands between Victoria's Corryong blaze and the two fires burning out of control at NSW's Kosciuszko National Park

Entire homes have been destroyed in Batlow following the bushfires over the weekend

Entire homes have been destroyed in Batlow following the bushfires over the weekend

Fire and rescue, as well as waterbombing helicopters, did their best to help out in Batlow on Saturday, but low visibility made it difficult and risky

Fire and rescue, as well as waterbombing helicopters, did their best to help out in Batlow on Saturday, but low visibility made it difficult and risky

Dozens of homes are feared lost in Batlow. Pictured: A property completely up in flames on Saturday

Dozens of homes are feared lost in Batlow. Pictured: A property completely up in flames on Saturday

Two Australian Army Soldiers help a family and their pup evacuate onto an Australian Army CH-47F Chinook helicopter at Omeo showgrounds on January 5

Two Australian Army Soldiers help a family and their pup evacuate onto an Australian Army CH-47F Chinook helicopter at Omeo showgrounds on January 5

Hundreds of homes are believed to have been across NSW, Victoria and South Australia after the catastrophic weekend - but that figure won't be confirmed until authorities can reach all of the affected communities.

Kangaroo Island, off the coast of South Australia, Batlow and Talbingo in the Snowy Mountains of NSW were all but destroyed over the weekend, when warm weather and strong wind gusts fuelled raging firestorms.     

Emergency Management Commissioner Andrew Crisp urged Victorians to remain vigilant, saying the weather will start to warm up on Thursday and Friday.

'What we are seeing with our weather, is yes, it is milder, it's more moderate, there has actually been some rain. But in terms of people thinking that this rain is going to put the fires out, that's not the case,' Mr Crisp said.

'There has been such a drought, particularly in the East Gippsland area, we know these fires are with us for a long time.'

While rain appears like a good outcome on the surface, a Bureau of Meteorology spokesperson said the little amount which is falling is actually considered a 'double-edged sword'.

The light rainfall, mixed with ash, actually makes conditions more difficult for fire fighters, who are now waiting for the drizzle to stop to continue backburning. 

Firefighters are in damage control to prevent further fires or property damage and have knocked over trees to stop them from falling in Corbargo

Firefighters are in damage control to prevent further fires or property damage and have knocked over trees to stop them from falling in Corbargo

This picture taken on December 31, 2019 shows a firefighter hosing down trees and flying embers in an effort to secure nearby houses from bushfires near the town of Nowra on the NSW south coast

This picture taken on December 31, 2019 shows a firefighter hosing down trees and flying embers in an effort to secure nearby houses from bushfires near the town of Nowra on the NSW south coast 

Some 18 communities in the state remain cut off after road closures and power outages saw supplies dwindle.

Victorian Premier Daniel Andrews confirmed six people are still missing after the fires, which destroyed more than a million hectares - 800,000 in East Gippsland alone.

In total, more than six million hectares of land has been decimated in the blazes, which have been burning since about October.

Authorities have warned that the fires will continue to burn for months.

'Based on the best estimate we would say [the fires will burn] for at least another eight weeks,' East Gippsland CFA incident controller Andy Gillham said on Saturday. 

'We are only at the beginning of summer. In a normal year we would start to see the fire season kick off in a big way around early January, but we're already up there at more than a million hectares of burnt country.

Kangaroo Island, off the coast of South Australia, Batlow and Talbingo in the Snowy Mountains were all but destroyed on Saturday. Pictured: A home in Batlow on fire

Kangaroo Island, off the coast of South Australia, Batlow and Talbingo in the Snowy Mountains were all but destroyed on Saturday. Pictured: A home in Batlow on fire

The death toll has risen nationally to 23 and 1,500 homes are thought to have been lost - with many in Batlow being burnt down

The death toll has risen nationally to 23 and 1,500 homes are thought to have been lost - with many in Batlow being burnt down

What does a state of emergency mean?

Declaring a state of emergency relinquishes decision making powers from the NSW government and allows RFS Commissioner Shane Fitzsimmons more control over his team of firefighters.

For the next seven days during the state of emergency, can now control and coordinate the allocation of government resources, close roads and evacuate residents.  

Ms Fitzsimmons has the ability to: 

Control and coordinate the allocation of government resourcesEvacuate people from property within declared areasClose roads and thoroughfares to trafficPull down or shore up infrastructure at risk of collapseShut down utilities in the declared area including electricity, gas, oil and waterEnter or take possession of property for emergency response

NSW Premier Gladys Berejiklian previously said the 'decision to declare a state of emergency is not taken lightly.

'You only declare states of emergency when it's absolutely necessary and on expert advice from commissioners.' 

It is the third state of emergency she has declared since the start of this year's horror bushfire season, which has seen at least 18 people die and thousands of homes destroyed.

A firefighter works to contain a small bushfire which closed the Princes Highway south of Ulladulla, Australia, January 5

A firefighter works to contain a small bushfire which closed the Princes Highway south of Ulladulla, Australia, January 5

'We are in it for the long haul, this is a marathon event, we expect to busy for at least the next eight weeks.'   

Meanwhile in NSW, Premier Gladys Berejiklian admitted the fire conditions were 'unprecedented'.

'We can't pretend this is something we have experienced before - it's not,' she said on Sunday.

'The weather activity we're seeing, the extent and spread of the fires, the speed at which they're going, the way in which they're attacking communities who've never ever seen fire before, is unprecedented.'

The premier's comments came as 47-year-old David Harrison died battling a blaze near Canberra on Saturday night, making him the ninth fatality in the state since Monday. 

Mr Harrison died of a heart attack after returning to a car to refill water to help battle a blaze at his friend's.

He had travelled to Batlow from his home in Goulburn to help his friend Geoff battle the blaze. He has been remembered as a hero. 

David Harrison (pictured) has been identified as the man who died helping a friend save his home near Canberra on Saturday night

David Harrison (pictured) has been identified as the man who died helping a friend save his home near Canberra on Saturday night 

Mr Harrison's brother Peter told 9News his brother would 'do anything for anyone'. 

'He didn't want to leave Geoff on his own. He was just that sort of guy. He would help anyone at the drop of a hat - he would drive hours to help you,' Mr Harrison said.

'He's a hero in our eyes.' 

Mr Harrison said David and Geoff had planned to evacuate but he believes they were 'overcome with the heat, smoke, exhaustion and running around putting out spot fires everywhere'.   

There were 150 bushfires burning in NSW on Sunday with 60 uncontained. About 50 continued to burn across Victoria.  

NSW Rural Fire Service  Commissioner Shane Fitzsimmons warned residents not to become complacent.

'We are seeing an easing of conditions right across the state and there's even a bit of drizzle down on the South Coast,' the commissioner told reporters.

A kangaroo rushes past a burning house in Conjola (pictured) on New Year's Eve, as officials prepare for a 'horrible day' on Saturday, with blistering temperatures and high winds likely to make conditions far worse

A kangaroo rushes past a burning house in Conjola (pictured) on New Year's Eve, as officials prepare for a 'horrible day' on Saturday, with blistering temperatures and high winds likely to make conditions far worse

How to donate to bushfire relief funds  

Victorian Premier Daniel Andrews has begged people to donate money rather than items, saying many stations are at capacity.

'I don't want to appear harsh in any way, but we don't need any more clothes, food, trucks on our roads,' he said on Sunday.

'I know it all comes from a place of kindness and I thank everybody who's made those donations.'

The CFA, Victoria's rural fire service, echoed that call: 'Experience tells us that donation of money is much more effective and provides more flexibility than the donation of material items or pre-loved goods.'

STATE FIRE SERVICES

Donations can be made to the state-funded rural fire services. Some states allow pledges to individual brigades.

Victoria: search 'CFA Donate'

NSW: search 'NSW RFS donate'

South Australia: search 'CFS Foundation'

Queensland: search 'Donate to RFBAQ' to donate to individual brigades

FALLEN FIREFIGHTERS' FAMILIES

The NSW RFS has established official funds for

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