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Synoptic situation: A look at the weather Extreme conditions make for remarkable records Satellite camera captures bush fire smoke plumes Violent end to three weeks in the broiler Fire captain engulfed in flames
Australia will never forget New South Wales burns while Victoria shivers January 2002 Australian summers are never known for their temperate comfort, but Christmas 2001 presented an extreme face, when blistering heat straight from the desert brought the New South Wales coast to flashpoint. 170 homes and hundreds of thousands of hectares of bushland were reduced to cinders, with insurance companies recording 3000 claims totalling more than $70 million. Graphic images of wildfire - especially from the volatile Blue Mountains - were startling. Exploding fireballs tore from tree top to tree top more than 30 metres high. The landscape proved a harrowing enemy as flames roared up gullies with a vengeance. As fire crested the tops of forested ridges its own violent wind blew the flames flat to the ground. The Devil was at the bellows, stoking up his forge for a brutal month of larrikin antics. Sadly, with more than half of the fires lit by arsonists, it appears the Devil had the upper hand. Australian surface pressure Two huge low pressure cells migrate east under the Australian continent between Christmas and New Year driving an endless procession of westerly winds across the coast of New South Wales. The first low is seen here south of New Zealand measuring 980mb while the second low, at 970mb, is in the Great Australian Bight. These two lows are unusually deep for summer, creating westerly winds to their north reminiscent of winter. Trouble is, it ain't winter in the desert and all that heat is pushed to the coast, helping to fan fires ignited in already tinder-dry conditions. The first factor in the Christmas fires was the dry nature of the New South Wales' coast. December was a real lack of rain on the coast from early winter onwards. Fanning these extremely dry conditions were two huge low pressure cells moving slowly under the continent and centred further north than usual. But their arrival was preceded by a season of similar, albeit smaller systems. Throughout spring and early summer, mid-latitude jet streams had been tracking closer to Australia than in previous years, bringing the influence of low pressure cells to the coasts of South Australia and Victoria. As winds circulated clockwise around these systems, they drove brutally dry heat from the arid interior onto the NSW coast - bringing a tinder-dry situation to flash-point. But it wasn't dry everywhere. Cold moist air off the Southern Ocean was a by-product of these continent-hugging lows, recording the wettest start to South Australia's summer in years. That state typically enjoys a Mediterranean climate with hot dry summers and cold wet winters. Victoria shivered under a similar influence, with the coolest spring and start to summer recorded in 100 years. December 29 was the only day in the whole month that the temperature touched 30 degrees. Western NSW and outback Queensland also enjoyed a wet start to summer as a persistent trough dumped enough rain to cause minor flooding in the weeks after the big fires. December 26, 0200gmt, 2001 This infra -red image shows the ingredients for fanning the Christmas-New Year fires in Australia: A powerful upper level jet from the north-west and a huge, rotating low at surface level. Squalls from the south-west brought snow to the high country of Victoria, but incredibly dry winds - often below 10 per cent humidity and reaching fiver per cent - were the norm right along the NSW seaboard. The complex nature of this first big low was illustrated when a pocket of cold upper level air reacted with opposing winds to produce a water spout of Jervis Bay, about five hours after this image was taken. The pocket of cold, upper level air is seen here over Melbourne. Black Christmas, searing New Year The first of the two huge lows - easily 1000 miles in diameter - approached the Tasman just before Christmas, driving a series of cold fronts across the NSW coast. Along the NSW and Queensland border, north-west winds ahead of these changes delivered brutal heat to a normally balmy environment. The thought of a traditional roast for tea was simply unbearable. Christmas day was a bloody hot one, mate, with 39 degrees (105 degrees F) recorded in Brisbane, 45 degrees (112 degrees F) in Cloncurry and under the influence of an unusual heat low, the northern New South Wales coastal towns of Ballina and Evans Head recorded temperatures touching 40 degrees. Down in the high country of Victoria it was a different world. Falls Creek and Mt Hotham residents experienced something many northern hemisphere residents rarely see: A white Christmas. A dusting that day was followed by nearly three centimetres on boxing day. Two centimetres fell again on January 2. Embedded within the general westerly rotation were pockets of cold air in the upper layers. On Christmas eve, one such pocket combined with relatively warmer air at the surface to generate violent thunderstorms across northern Tasmania. Following hard on the heels of one of these storms was an unusual twister, created by temperature and wind direction differences within the column of disturbed atmosphere. The 'mini-tornado' cut a swath of destruction through Summerhill, 10km southwest of Launceston ripping off roofs and damaging more than 100 houses. A similar weather window created several dramatic waterspouts off Jervis Bay, New South Wales, two days later, literally colliding with the leading yachts in the Sydney to Hobart yacht race. East Coast of Australia and
Tasman Sea The yellow arrows in this infra-red image point to smoke flowing east-south-east into the Tasman Sea towards New Zealand. Most of this smoke is from intense bush fires in the Blue Mountains, west of Sydney, and on the NSW South Coast near Jervis Bay. The heat of the fires has lifted the smoke close to 10,000 feet in the air, where a strong north-westerly jet has taken it on a ride. At surface level, hot dry westerly winds north of Sydney created temperatures into the low 40s and humidity as low as 5 per cent - a new record. Meanwhile squall clouds behind embedded cold fronts within this huge low pressure cell, dumped a dusting of snow on the Victorian Alps! The ferociously hot north-west to west winds ahead of these fronts were a major factor behind the fires. and you can see the boundary between them and cooler south-west winds just south of the smoke plume. Bushfire weather reminiscent of 1994 Interestingly, Dr Milton Speer of the Bureau of Meteorology in Sydney says the general synoptic weather pattern was almost identical to the that of January 1994, which also caused devastating bush fires up and down the east coast. Normally, you can expect a powerful low to whip the south-east of Australia with a sharp cold front, bringing heat to our district and cold - even snow - to the alps. But just as quickly as it would come, the wild weather would disappear out into the Tasman as the low moved away to the east. Rain showers and a cool southerly change would ease the heat in the north while high pressure would move over the southern lands of Victoria and Tasmania, bringing summer sunshine and balmy conditions. This time, however, both lows began to form more than one centre, with each of these lesser lows rotating around a general centre like dumbells. With each low came a cold front with its inherent wind changes, wreaking havoc on firefighters controlling the big blazes with back-burning operations of their own. In the case of one volunteer fire captain, an early southerly change created a potentially fatal situation and his experience was not alone during Black Christmas. Restless upper-level winds Because the two lows were so large and so close together, westerly winds higher in the atmosphere refused to back to the south. Winds on the surface quieted for a day as a narrow ridge of high pressure acted as an intermission between the two large lows. Tailenders in the Sydney to Hobart race were able to enjoy one of the kindest Bass Strait crossings - unlike the leading yachts. But the cool southerly change at the surface was short lived. And north of Sydney the change could hardly be called 'cool'. Sydney itself recorded its lowest humidity on record - just five per cent - as bush fires ringed the city and the famous harbour bridge disappeared behind a veil of smoke The westerly winds aloft were relentless and dragged desert-dry air from the interior well out into the Tasman. Satellite images of Australia and New Zealand showed visible traces of smoke well out into the ocean and Auckland noticed hazy conditions as a result of the Australian fires. Meanwhile, New Zealand climatologist Dr Jim Salinger said the heat of bushfires and westerly winds aloft were ideal for lifting and transporting insects across the Tasman. He said there had been an invasion of Australian butterflies in April 1971 when Australia was under similar conditions. In October 1967 grain aphids from Victoria were discovered in New Zealand when similar upper level winds were able to transport them across the Tasman. But for New South Wales firefighters, these wild westerlies made firefighting a game of synoptic chess. Hot and gusty At times, throughout the ordeal, westerly winds roared over the dividing range from 3000 feet upwards. Some nights a synoptic inversion layer would form, with warmer air at the surface and cooler air above. As long as the two layers remained constant, the westerly jet would skim across the top of the denser cooler air like a skater on ice. Come midday, after the heat of the sun warmed the earth, this inversion layer would begin to break down. Like a lava amp, warmer air would leap upwards, mixing with the westerly jet and driving short bursts of the powerful westerly jet towards the ground. Those bursts of wind created hot and gusty conditions on the ground, with the direction backing and veering 20 or more degrees from west. Backburning attempts begun in the calm of the morning blew out of control, forcing firefighters to beat a hasty retreat. Bumpy terrain also created havoc with the hot westerlies, particularly in the rugged Blue Mountains, where winds were funnelled up gullies and created swirling eddies on the lee side of steep mountains. These local synoptic conditions were impossible to predict from headquarters. Firefighting in these backblocks required the most experienced of local bush knowledge. Violent end to a month of destruction As if to remind her subjects about the range of her emotions, mother nature dealt a cruel blow of a different kind to north-eastern New South Wales on the very day that the three-week-long bush fire crisis was officially declared over. As high pressure pushed into the Tasman on January 16 it extended a ridge along the North Coast of NSW. Above this surface high, as low as 800mb, winds flowed from the south-west before curving to the east and then south-east over the southern Coral Sea. Embedded within the south-west flow was a pocket of cold air, which began to spiral, forming an upper level low. Add to this heady mix a mild monsoonal trough extending south-east from the Northern Territory to the NSW and Queensland border area. As surface winds flowed counter-clockwise over the top of the high pressure ridge, they blew moist ocean air onto the coast from the east-south-east. Winds just a few thousand feet above blew cool south-west and tropical humidity embedded in cold upper-level air - the monsoonal trough - helped to lift these opposing winds to great heights. These are classic severe storm ingredients and the result was a powerful band of thunderstorms sweeping north along the coast of NSW wreaking havoc on fruit growers near Grafton and Coffs Harbour as hail destroyed mandarins and grapes. In Lismore wind and hail destroyed carports and windows and uprooted trees. But the storm cell re-formed as it approached the border area of Tweed Head developing a large and intense core that dropped golf-ball sized hail over a wide area. Kingscliff near Tweed Heads bore the brunt of the storm with the North Coast's total damage bill estimated at $5 million - not including damage to crops. A quick look at the surface pressure map that morning revealed very little of what was to happen that afternoon. Which goes to show that being weather-wise involves a three-dimensional approach to nature. If there was one good thing about this violent change, it was the cool southerly air it brought the NSW coast. As high pressure filled the combination of surface and upper atmosphere winds locked this high in location for more than three days. Cool south-east winds brought easy temperatures well below 30 degrees for the first time in weeks. In the high country above Coffs Harbour, night temperatures dropped low enough to light an evening fire, while back on the coast long pants came out of the closet - if only for the early mornings. The heat has abated for the moment, but until serious rain arrives the threat of fire will always linger. © Jamie Brown/weather-wise.com 2000 Engulfed in flames Bush fire training survives a reality check New South Wales Bushfire Brigade captain Daniel Ainsworth will never forget Black Christmas, 2001. At the tender age of 20 he is one of the state's youngest fire brigade captains but when it comes to experience this young leader has chalked up the distance. He became a bush fire volunteer at the age of 14, after the horrific 1994 bush fires, and never looked back. Today he leads his local brigade, just like his father, Greg, before him. And, like his dad, Daniel leads training exercises to prepare his fellow volunteers for the worst possible scenario. On Christmas day, however, he found out first-hand that training and real drama are two different creatures. Daniel started his firefighting shift Christmas morning about 10am in perfect conditions. Winds were light and a new fire, across the Pacific Highway in State Forest between the Clarence and Richmond Rivers was all but inactive. The plan was to smash smouldering stumps and generally mop up to make sure no new blaze could re-ignite. But that plan, like so many fire plans made during the hectic Christmas - New Year's week, was discarded when a gusty nor-wester piped up about midday and the brigades retreated to the safety of the Pacific Highway. At this point Daniel and another crew together with the brigade truck, were sent to a property on the eastern side of the highway to make sure it would be secure. Trapped! About the same time a private contractor's skidder and a National Parks and Wildlife Service were brought to the property to create firebreaks around a planned back-burn. But while they were at the bush property, a smouldering gum leaf blew across the highway and a new fire ignited - cutting off an exit back to safety. All back-burning and fire-break clearing efforts were cancelled. "We were in no danger at the time," recalls Ainsworth. "So we continued with property protection work from about 1pm onwards. We knew something could happen so we cleaned gutters and flammable fuel around Claire's house. We expected to be able to control spot fires and that way might save the house." All afternoon the gusty nor-wester continued and everyone in the evening. The Bureau of Meteorology continued to advise the Rural Fire Service which in turn kept the brigades on the ground in-the-know. Trouble was, the Christmas conditions weren't so cut-and-dried. Sure a change was due and ordinarily one could set a clock on its arrival, based on how quickly it arrived at Coffs Harbour, then Yamba. That was not to happen this time around ... Fire storm! About 7pm a gentle southerly change blew through Claire's property - at least 45 minutes ahead of schedule. While the wind blew at less than 15 knots, it fanned flames into an area of dense bush and quickly accelerated. The fire was now creating its own storm and Ainsworth and his crew had literally three minutes to prepare themselves for the onslaught. "We couldn't get out, so we put the truck in a safe spot - the driveway - where there was no fuel underneath. We kept the engine running and the motor for the pump at the back of the truck going - typically the truck itself catches fire and must be put out as soon as the fire storm blows over," he said. "This time the fire came on us so quickly that we didn't even have time to offload jerry cans of fuel of the truck." At this point it was pitch black with the smoke, and all they could hear was the roar of the fire racing towards them. Daniel and his crew along with Claire, the property owner, and her brother-in-law and her dog, jumped in the cab and followed training procedure: Daniel turned on the sprinkler system outside the cab of the truck - a new system developed by a local welding company which sprays directly at the windscreens - covered themselves in fire-proof woolen blankets and maintained radio contact with Rural Fire Service controllers back at the highway. For the next eight minutes, flames 10 metres high and more roared over the truck and from inside, its passengers witnessed a living hell. Like a bomb Claire, who has spent the last 19 years restoring a multitude of ecosystems on her bush property, described the next eight minutes as if "a bomb had gone off'. "It all happened very, very quickly," she recalled from her blackened forest. "It was like a bomb had exploded everywhere. There was a cracking sound in the trees, the tops of trees were blowing off and landing on things. From inside the truck I just couldn't believe what was burning. I watched as a Hessian bag inside the machinery shed just erupted into flame while outside whole trees exploded into a ball of fire." The skidder and tractor, parked just five metres from the brigade truck, burst into flame and when the fire cooled the tractor's wheels were literally twisted from the burden of heat. Within three minutes of the fire moving through, local brigade captain Rick Teudt and his crew drove through the smouldering bush to help Daniel, Claire and the rest of the those in the truck. Despite the hellish nature of their ordeal, everyone was fine. The truck was unscathed and the people inside it hardly felt the heat. Surprisingly Claire Kennedy's house didn't burn. However, Claire found that her home was indeed singed. Everything made of plastic had melted - buckets lying on the ground, PVC guttering, the shade cloth over her fernery - all melted beyond recognition. Her equipment shed was destroyed along with three small tractors - but her most valuable possession - her beloved bushland - presented a very different face. "All the vine forests, and staghorn fern forest were gone," she recalled later. "Wildlife was lying dead all over the blacked forest floor - wallabies and kangaroos, a glider, reptiles ... I've seen a lot of fires in my 19 years here but nothing ever like this.‘" As for Daniel Ainsworth - this experience will serve him well in coming years. But the question remains ... how scared was he? "They tell me I was calm on the radio," recalls Ainsworth, "But I was very scared. We all train for something like this, but there is nothing like the real thing." © Jamie Brown/weather-wise.com 2000 |