New blaze fears for Australia as weather conditions could turn bushfire into devastating 'fire cloud' Catastrophic weather system is formed by fires in unstable atmosphere Towering clouds do not have enough moisture to douse ground below They can cause electrical storms which may spark more blazes Catastrophic weather systems known as 'fire clouds', sparked by heat from the raging bush blazes outside Sydney, could see south west Australia hit by devastating lightning storms. The dramatic cloud formations have already been seen over some burning parts of the New South Wales bush last week. But a merging of the biggest wild fires into one 'mega blaze' could see temperatures intensify and the atmosphere above the region made unpredictable and potentially dangerous. The clouds rarely carry enough moisture to cause the heavy rain which firefighters need to help them douse the spreading flames. Burning front: Firefighters have been working around the clock to bring the flames under control. Here officers in the Blue Mountains, west of Sydney, are met with a wall of flame Worst ever: Fire chiefs have said that if two of the flaming fronts meet, it could result in one of the worst forest fires Australia has seen Real danger: The effect of fire clouds can be devastating to already suffering disaster zones But they can be unpredictable enough to cause lightning strikes which could well set light to the already dry earth in South West Australia. Fire clouds are also known to scientists as 'pyrocumulus'. They occur over the sites of large scale blazes, like the ones which have ravaged the landscape around Sydney. They are caused when fires burn and the hot air which is released rises as a column into the atmosphere. When the air moves upwards, it is quickly replaced by cooler air at high altitudes, a process which leads to a convection column. In large bushfires, these hot-air columns can grow to enormous proportions, rising high into the atmosphere carrying a large amount of water vapour, which is one of the main products of fire. Seen from space: The fire clouds, or pyrocumulus, are caused when the heat from the flames enters the atmosphere above. This satellite image shows smoke streaking from south west Australia Towering example: This pyrocumulus, which appeared as a result of forest fires near Yellowstone National Park, USA, shows the imposing nature of the weather system Eventually, the column rises high enough into the atmosphere for the temperature was to be cool enough for the water vapour to condense into a pyrocumulus cloud. Rural Fire Service spokeswoman Natalie Sanders confirmed a pyrocumulus was apparent over the State Mine fire, which stretched across more than 42,000 hectares, last week. Asked if she believed there weather systems could reappear of the disaster zone, she told the Sydney Morning Herald: 'If these fires are still going strong, there's a potential for that to happen again.' The likely cause of such a dramatic cloud would be the coming together of two of the biggest fires in New South Wales. Officers are doing all they can to try to prevent the two infernos, one near between Lithgow, west of Sydney, and another close to Springwood coming together. Helping hand: A swamp wallaby, which has fled into nearby water to escape the raging fires is rescued by a local resident Pet rescue: Lake Macquarie local Ryan Baxter, above, said: 'It was probably a good 50m from shore. The fire just raced down the shoreline and the animals got trapped. Survivor: This baby swamp wallaby was named 'phoenix' after it survived the flames. There is growing concern for the wildlife in the bush of New South Wales with the fast moving nature of the fires especially dangerous They have even deliberately merged smaller fires in the area surrounding the Blue Mountains, in a bid to make the blazes easier to manipulate. Fire Service Commissioner Shane Fitzsimmons believes crews would be faced with the worst bushfire ever to hit New South Wales if the two were to meet. Commissioner Fitzsimmons said: 'I don't think I've ever used the word mega-fire. Hard earned rest: A firefighter is slumped over next to his engine after a long operation in the Blue Mountains Flat out: Officers have been working around the clock to evacuate residents and battle the blazes. Only person has died so far Plan of action: The crews' main concern lies with two burning fronts to the west of Sydney 'But the reality is that the modelling indicates that there's every likelihood that in the forecast weather conditions, these fires, particularly in the back end of the mountains, will merge at some point.' While fire fighters tackled the flames, members of the public were helping by rescuing wildlife from burning woods. Locals near Lake Macquarie at Chain Valley Bay, took to the water to fish out swamp wallabies which had fled their forest homes. One resident, Ryan Baxter, said: 'The fire just raced down the shoreline at Chain Valley Bay and the animals got trapped. They would have been burned alive if they didn't swim.' Assessing the damage: Karen Bousfield, returns to her in home Winmalee, some 80 km west of Sydney, which has been gutted by fire Unrecogniseable: A dog stands next to what was once its owners home in the Blue Mountains, just outside Sydney What remains: A young boy stands by his grandfather's car which was consumed by flames in Winmalee