GEOGRAPHIC EXTREMES SOCIETY
AUSTRALIAN RECORDS
Storms in Australia
Storms are among the deadliest of all-natural disasters in Australia, with only heatwaves resulting in a larger loss of life. Storms are best described as destructive atmospheric disturbances, capable of delivering intense, strong winds, rain, thunder, lightning, hail, snow and dust, or a combination of these. No one in the world is immune from storms.
It’s difficult to compare the severity of storms. While most meteorological organisations use wind speed to classify storms, others consider the economic costs, or the loss of life, as an assessment of the ferocity of storms. I am sure we can all agree that these are all worthy indicators. In the end, I have adjudicated the best way to determine storm records, is by measuring the atmospheric pressure, the principal driver of storm savagery.
When Australians think of the worst storms, tropical cyclones are rightfully the most feared. Tropical Cyclones like TC Tracy which destroyed Darwin on Christmas Day in 1974 or more recently the immense size of TC Yasi which battered Cardwell in 2012. We will get to Tropical Cyclones soon, but first, let’s consider other major storm types that afflict Australia.
East Coast Lows
East Coast Lows are a significant storm type which affects the greatest proportion of the Australian population, much more than Tropical Cyclones. East Coast Lows form close to the eastern Australian seaboard between the central Queensland city of Gladstone, south to the border of New South Wales and Victoria, which roughly equates to 25o to 35o south of the equator.
The fast-moving East Coast Low weather system, has the potential to mimic a Tropical Cyclone in rainfall intensity but is shorter-lived, rarely get atmospheric pressures below 1000 Hpa, and while winds are gale force, they don’t achieve the velocity of cyclones. Unlike cyclones who acquire their energy from warm oceans, the formation of East Coast Lows relies on temperature gradients in upper atmospheres between the continent and the Tasman Sea.
The gale-force winds produced by these lows, produce exceptional large waves and rough surf, capable of severe disruptions to the East Coast Sand River[1]. An East Coast Low was responsible for the Collaroy erosion event of 2016, when houses along Sydney’s northern beaches, lost swimming pools and foundations when swamped by large waves that removed 400,000 m3 of sand waswashed back out to sea. It is an all too often occurrence. Another Low unleashed wild surf which smashed through Jumpin Pin on Stradbroke Island in 1898, dividing the island into the two. One hundred years later, the Jumpin Pin Bar entrance is over a kilometre wide. These storms have the potential to be major catastrophic events.
Largest East Coast Low in Australia
Recent in many Australians memories is the 2007 East Coast Low which saw the grounding of the large coal carrier, Pasha Bulka on Nobby’s Beach, creating an unwanted tourist attraction just a stone throws away from Newcastle’s city centre. This very conspicuous grounding was the most current in a list of storm-related shipping mishaps along the east coast and it wasn’t the first time at Newcastle. It’s a story that gets repeated too often. When we examine the shipwrecks along Australia’s east coast, it reads like a who’s who of East Coast Low tragedies. In 1974, another coal carrier, Sygna, ran around on Stockton Beach just four nautical miles north of where the Pasha Bulka ran aground. Named the Sygna storm, this East Coast Low resulted in the strongest wind gust measured in New South Wales at 165 km/h[2]. The carcasses of dead ship litter the entrance to Newcastle’s harbour starting with PV Cawarra, in 1866, was wrecked on Newcastle’s notorious Oyster Bank, what is now the Stockton breakwall.
The Sygna Storm may have been the windiest measured so far but certainly not the deadliest. East Coast lows have been wrecking havoc on the eastern seaboard for centuries. One of Australia’s worst shipwrecks was the Dunbar who ran into The Gap near Sydney Heads during an East Coast Low storm in August 1857. Of the 122 crew and passengers. only one survivor, James Johnson, who for two days remained undiscovered under an overhang, still clinging to the cliffs. Johnson went on to become the lighthouse keeper at Newcastle, where he rescued the only survivor of the PV Cawarra, wrecked in a similar East Coast Low storm nine years later at the Hunter River’s oyster banks.
Another famous shipwreck, courtesy of an East Coast Low, took place off the Cooloola Coast in July, 1973. The Cherry Venture was travelling between Auckland and Brisbane when the storm forced her aground on this popular camping beach. For thirty-four years her hulk lay rusting until National Parks deemed it a hazard and had this well-known attraction removed.
The pattern of East Coast Lows we have documented so far, would have you think of them as winter storms. While its true the vast majority are experienced between May to September, East Coast Lows can also be savage summer storms and prove to be just as deadly. In the 1998 Sydney to Hobart Yacht Race, an East Coast Low saw the sinking of five yachts and six sailors lose their lives. The storm bought unseasonal snow to the Australian Alps and enormous swells and gales to the east coast. It was the largest peacetime search and rescue mission at sea in Australia’s long maritime history. The race management committee and the Bureau of Meteorology came under fire at the Coroner’s Inquest and recommendations led to better forecasting and a communications tower being built on Mount Imlay, near Eden.
Of course, the west coast of the continent experiences some extreme storms as well. Intense cold fronts drifting across southern Australia have the potential to unleash strong winds and rainfall, and once again these are experienced mostly in the cooler winter months. These mid-latitude lows and cold fronts are embedded in the westerly wind bands which sweep the Southern Ocean, often delivering severe storms to Western Australia’s south-west, coastal South Australia, Victoria and Tasmania. The winter cold front storms usually bring intense bursts of rain or snow, accompanied by strong winds to southern Australia. The Bureau of Meteorolgy issues Sheep Graziers Alerts for the protection of livestock during the most intense cold fronts. While these alerts usually go out during the coldest months of July and August, they can go out at any time of the year. Some of the frontal systems don’t deliver any rain at all, but whip up dust storms which carry millions of tonnes of top soil eastwards.
Largest dust storms in Australia
The highest frequency of dust storms occurs in central Australia. Alice Springs sees an average of 10.8 dust storms per year with a maximum of sixty-five events in a single year. Massive dust storms which reach the east coast are generally restricted to the drier years during the El Nino cycle. It must be noted though, even though Australia is a very dry continent, our dry rangelands don’t produce much dust as compared to the Sahara, the Arabian Peninsula and the Gobi Desert. The Sahara produces almost twenty times the annual dust as Australia and the Gobi deserts dust causes constant problems for the densly populated Chinese east coast. In China, the recent profusion of dust storms is being blamed on overgrazing by goat herds. A problem Australian land managers make take heed of.
When we look back at the history of dust storms in Australia, the 1940s were by far the greatest incidence of dust storms. We measure duststorms by the Duststorm index, or just DSI and the DSI was far greater in the 1940s than today. Much of the blame for the early dust storms was laid at the feet of rabbits, who denuded southern Australian pastures for almost a century before the Myxoma virus was released in the 1950s. It also appears that since 1975, Australia’s average wind speed has dropped as land management techniquies improve.[i]
The much-lauded Red Dawn dust storm which blanketed Sydney and the entire eastern seaboard of the continent The Red Dawn dust storm engulfed eastern Australia on September 2009. It is particularly remembered in Sydney where it was estimated to be the largest since records began in the 1940’s in regards to loss of visibility. Since the 1960s we have also been able to measure dust particle loads driven aloft from dust storms. The Red Dawn storm carried up to 17.5 million tonnes of dust aloft and transported over 2.54 million tonnes offshore. The offshore component fell mainly into the Coral and Tasman Seas but also sent dust over New Zealand and as far away as the Andes in South America.
Cyclones
Cyclones are Australia’s largest storms and are capable of inflicting widespread damage in a very short amount of time. You hear stories of animals acting unusual at the approach of significant storm like cyclones, but my experience differs. The approach of Tropical Cyclone Steve in 1999 had me going around observing any impending doom from the surrounding wildlife and I was quite disappointed. There were pigeons mating, dolphins doing the same laps of the coast, young male agile wallabies playing fisty-cuffs and pythons sunning themselves in their favourite spots. I was surprised that the plummeting barometer provoked little to no immediate distress amongst the local wildlife, because cyclones are savage.
Longest lived cyclone
The longest-lived cyclone recorded in Australian history was most probably Tropical Cyclone Justin in March 1997. For eighteen days the cyclone wandered the Coral Sea and across Queensland’s northern coastline. This pales in comparison to Typhoon John in 1994, which travelled 13,180 kilometres across the northern Pacific and lasted for thirty-one days. TC Justin developed into a category one tropical cyclone off the Great Barrier Reef before slowly moving north and devasting the Lousiade Islands in Papua New Guinea before moving back to Australia to cross the coast north of Cairns. I was living on the Atherton Tablelands at the time when it passed over, to great anticipation from our household but by then winds had dissipated and we only lost a single pawpaw tree.
Furthest travelling cyclone
Tropical Cyclone Steve in 1999, could possibly be the cyclone that travelled furthest in Australian waters. It formed just off Cairns and crossed the coast at Trinity Beach where I was living at the time, obliterating our local hotel and sending trees crashing on our roof. It was downgraded to a low after crossing the coast, before moving into the Gulf of Carpentaria and reforming into a cyclone, creating havoc for gulf communities and fishing fleets. It again crossed the coast near Roper River in the Northern Territory before being downgraded to a low once more. TC Steve continued its drift west before entering the Timor Sea and acquiring extra energy from the warm seas to reform as a cyclone. Its path followed the coast of Western Australia’s from Broome to Shark Bay, before it once again crossed the coast into the Murchison and Goldfields regions, ultimately being downgraded to an extra-tropical low-pressure system and passing into the Great Australian Bight, expiring after a journey of 6000 kilometres over thirteen days.
Largest tropical cyclones in Australia
It is Tropical Cyclone Mahina which is most lauded to be the largest cyclone to strike Australia. In March 1899, TC Mahina crossed the coast at Bathurst Bay on Cape York Peninsula, killing up to 400 people, making this one of the deadliest natural disasters in Australia’s history. The cyclone also produced a reputed world-record storm surge of 14.5 metres and a record-low southern hemisphere storm pressure of just 880 hPa. Something I’m sure you will soon agree is wanting.
The World Meteorological Organisation has an extremes archive which blindly states that TC Mahina’s storm surge is the highest on record for the world. This cyclone has recently garnered a lot of attention from researchers and many have cast the records into doubt. You may remember that it was Clement Wragge who was Queensland’s Chief Meteorological Officer at the time of TC Mahina and he wasn’t averse to accumulating climate records.
The vast majority of lives lost in TC Mahina were from a pearling fleet, sheltering in the lee of Cape Melville and the veracity of records belong to second and third hand reports. The barometric records are attributed to Captain Porter, aboard The Crest of the Wave, which rode out the storm in Bathurst Bay. The best known report of Tropical Cyclone Mahina was written just a few months after the event and it clearly stated that Porter observed the barometric pressure at 27” or what is 914 hPa today. This was taken as the Australian record until later research uncovered a letter from Captain Porter stating the pressure dropped to 26” or 880 hPa. Note these are both round figures in a day and age when barometric pressure was measured in inches and points of an inch. Seventy years after the cyclone, many meteorologists quickly reprinted the record books to take Captain Porter’s historic letter into account, however, even ships which rescued Porter, were incredulous to Porter’s claim. As with many records during Clement Wragge’s tenure, inconsistencies are far too frequent.
The claim of TC Mahina producing a world-record 14.5-metre storm surge at nearby Ninian Bay is a profound exaggeration and the reluctance of the World Meteorological Organisation to address this in their records, taints this institutions reputation to deliver the facts. The storm surge report comes from a Cooktown policeman, Constable Kenny, who was investigating an unrelated matter at Ninian Bay when TC Mahina passed overhead. He claimed that the ridge he was camped upon was half a mile inland and forty foot above the high tide mark when it was covered by an incredibly large sea that reached half way up his torso. There is no mention of this tidal surge delivering driving waves or whether this rounded up 40 foot measurement included wave run up. Thankfully his entire party escaped unscathed. A party of colonial officers from Thursday Island went to inspect the pearling fleets damage and doubled down on the height claim saying an indigenous tribesman pointed out timber resembling a canoe, 70 foot up in a tree fork, as if to indicate to their Brisbane superiors that the storm surge was much greater. Anyone who knows the Starke and Cape Melville region, will quickly tell you that a 70-foot high tree is very hard to come by next to the coast. This is an extremely windy coastline with nutrient-poor soils which effectively stunts most trees.
Every simulation model over the last fifty years that has replicated TC Mahina’s storm surge at Ninian and Bowen Bay, falls well short of a world record and fail Constable Kenny’s claim. Researchers from James Cook University have recently attempted to explain the irregularities with TC Mahina which may account for the record nature of this cyclone, but even with the most generous parameters, all models fail to produce anywhere near a 14.5 metre storm surge. Sadly, the World Meteorological Organisations record is based on vague estimations and rounded up values of height and barometric pressures.
The loss of life from TC Mahina cannot be underestimated, but even here major discrepancies again surface. We know that the crews of pearling fleets were decimated but there are claims of entire indigenous tribes being washed into the sea while helping stricken pearling luggers. Some of these accounts may be true, but research points to huge inaccuracies here as well. The best accounts of the event show a loss of 307 lives from ships and an unknown number of indigenous rescuers.
Evidence for TC Mahina as being the largest cyclone in Australia is highly debatable, lacks evidence and comes from flawed sources. So, what then is the largest authenticated Tropical Cyclone? The Bureau of Meteorology archived records, show this is jointly held by TC Gwenda in 1999 and TC Inigo in 2003, both of which were estimated to be 900 hPa in pressure. Both of these storms were in Australia’s meteorological zone of influence and named by the Bureau of Meteorology, however, only TC Gwenda was within Australian waters, the Exclusive Economic Zone, when the peak intensity of the storm was reached.
Highest wind speeds in Australia
For the greater part all storms bring wind. The Bureau of Meteorology have a vast network of anemometers which measure the wind near ground level and as a rule, they don’t accept wind speed generated by tornados, dust devils or waterspouts. The Bureau’s record for the strongest gust of wind was from Tropical Cyclone Vance which crossed the North West Cape in 1999. The Bureau’s anemometer at Learmouth Airforce Base near Exmouth and Ningaloo Reef, registered a wind gust of 267 km/h. TC Vance still holds the record for the highest wind gust ever recorded on the Australian mainland but it is by no means the strongest gust of wind registered in Australia. The fact of the matter is Australia holds the world record in wind gust strength.
In 1996, just three years before TC Vance, TC Olivia passed by Barrow Island off the coast on April 10, 1996 delivering to the Island a massive series of gusts culminating in a world record 408 km/h wind speed. Of course this had the whole of the world sit up and take notice, the record for wind speed was recorded at Paso Real de San Diego meteorological station in Pinar del Rio, Cuba at 340 km/h[3].
Concerns were immediately raised by meteorologists as the estimated speed of winds at the eye of TC Olivia was only 176 km/h, well less than half of what was recorded at the Barrow Island’s anemometer. It took almost a decade for the Barrow Island record to be authenticated, after apprehensions about the anemometer being privately owned by the energy multinational Chevron were addressed. But why was the speed recorded so different to the estimated cyclonic speed of the eye of the storm,
Upon examination of the record it seems there was something else happening with TC Olivia to generate such fantastic wind speeds. Blair Trewin, the principle researcher of the Bureau’s records was adamant that everything was legitimate. The 3 cusp anemometer had been recently calibrated by a handheld device, and the device was in a correct location above the ground and well exposed to wind from all directions. Chevrons team on Barrow Island were able to provide an excellent documentation of which led to the wind speed record, and this has assisted scientists to further our understanding of the physical nature of cyclones.
The extreme wind gust measurement was one measured during a five-minute tempest. Speeds of 369, 408, 374 km/h were observed followed by four gusts of less sustained speed. By less sustained we mean these intermediate gusts were still incredibly strong with a minimum of 211 km/h. These were followed by two more extreme gusts of 347 and 298 km/h during the same five minute period. Researchers have determined that a series of mesovortexs were present near TC Olivia’s eye, explaining the disparity in the estimated cyclone speed and the speed recorded. These mesovortexs resembled tornado like funnels embedded within the rapidly spinning eye of the cyclone.
I’m happy with this wind speed record but it does open a can of worms. Many people may ask, do embedded tornado-like vortexes nullify the wind record? This issue illustrates the blurred lines between cyclonic systems and tornados. The world record for a tornado wind speed is 486 km/h measure by doppler radar in Bridge Creek, Oklahoma, some eighty kilometres faster than the Barrow Island record. A tornado’s intensity is measured according to the Fujita scale. This scale starts where the commonly known Beaufort scale finishes at level 12. The Fujita Scale is theoretically divided into a thirteen-level scale, F0 – F12, finishing at the speed of sound, but no tornado has so far gone past F5[4].
Largest tornados in Australia
The largest tornado in Australia is estimated to be the Buledelah Tornado in 1970 which some calculate to be around F4 on the Fujita Scale but it is hard know without todays technology. This tornado spun off a very deep low pressure system which formed over central New South Wales and cut through a swathe twenty-two kilometres long and up to a kilometre wide. The most deadly tornado in Australia’s history is the 1971 Kin Kin Tornado which cost three lives. It appears from the reports of tornados in Australia, that they are increasing at a phenomenal rate, in fact tripling over the last few decades. A lot of this reported increase can be attributed to storm chasers whose invaluable input is helping to understand storms better on the continent.
While most storms deliver rain, large supercells produce violent updrafts which take rain droplets high into the atmosphere where they freeze, before gravity takes hold and sends them earthward. This circulation of rain to hail can happen many times over for the same water droplet, and they can grow each time into increasingly larger hailstones. There are some records for incredibly large hailstones, but what constitutes as a single hailstone is quite arbitrary. Stories of enormous hailstones are mostly agglomerations of many individual hailstones, some bound together whilst tossed around in the atmosphere, others are accreted when lying on the ground.
Largest hail storms in Australia
The most devastating hailstorm, in terms of economic losses, was the Sydney hailstorm in April 1999. This was an unusually late severe storm that moved northward from the Illawarra region and crossed the city after the peak hour commute. Between 7.30 and 8.15 pm the eastern, southern and lower north shore suburbs were torn to shreds in what can only be described as a freak storm. If it were to happen again today, over 4 billion dollars of damages would occur. Hailstones up to nine centimetres were reported and a load of 500,000 tonnes of hail was estimated to be dumped on the city.
Sydney is quite familiar with hailstorms. The most hail prone region of Australia is the eastern seaboard between Sydney and Brisbane with the triangle of Coffs Harbour to Port Macquarie and west to Armidale attracting the most hailstorms on average each year. Insurance companies have positioned themselves at the forefront of storm warning technology, due to market forces demanding better protection in hail prone area’s. Due to there efforts, we are now well aware of where and when these storms form. Insurance premiums now reflect which area need to build carports and have roofs of corrugated iron.
Most lightning-prone region in Australia
Most of the larger storms that Australians experience are thunderstorms. These are very frequent in Australia’s top end where it was once thought that Darwin was the lightning capital of the world. Forty years ago, trained observers in tropical regions were thin on the ground which led to this assumption of Darwin’s incredible monsoonal lightning displays. Today’s meteorological satellites are infinitely better at mapping lightning across the planet and paint a far better picture of location and lightning intensity. Measuring lighting strikes from space soon threw Darwin’s claim out the window and a more accurate idea of the most lightning prone region in Australia emerged.
The incidence of lightning is measured in Flash Rate Density, or FRD, which is how much lightning for every square kilometre per year. The region with the greatest lightning display on the planet is Lake Maracaibo in Venezuela with an amazing FRD of 232.52. Compare this with Darwin which ranks as the 355th most lightning-prone locality in the world with an FRD of 57.13. Australia’s most lightning-prone region is a section of the Regent River National Park in Western Australia’s, Kimberley region. It ranks 61st in the world with an FRD of 92.15.
From Broome in Western Australia to the savannah plains of Queensland’s gulf country, the lightning from summer storms provided indigenous Australians with spiritual stories to help explain their world. Visitors to Kakadu National Park will get an insight into indigenous dreamtime stories of lightning spirits at Nourlangie Rock art site. It depicts Namarrkon, a Leichhardt’s grasshopper which only emerges in the wet season. Further west in the Kimberley, the Wandjina figures display rain and lightning motifs to symbolise the spirits of the wet seasons storms. In Queensland’s Kalkadoon country around Mount Isa, Walter Roth documented stories of lightning creators and on Mornington Island, Precy Trezise recorded the Lardils peoples lightning stories.
The last word on storms comes from outside our atmosphere, in a new scientific field we call space weather. The main source of this weather is our sun and as we discovered in the first chapter on sunlight, it also drives atmospheric weather. Every single day we see this huge thermo-nuclear reactor overhead as it creates million degree temperatures by fusing hydrogen atoms into helium and generating unbelievably potent magnetic fields. If there was anything capable of bring our modern world to its knees it is an outburst of solar weather aimed directly at our planet from our life-giving and sometimes life-destroying sun.
In September 1859, the last significant solar storm struck the earth. On September the first and second, the Carrington Event, the earth’s largest Coronal Mass Ejection caused havoc to primitive telegraph lines and stations across Europe. Telegraph operators reported electrical shocks and some systems could even transmit even when unplugged. The Aurora Australis was observed for three consecutive nights as far north as Brisbane and miners in Victorian goldfields reported intense aurora effects.
Our sun sometimes erupts with solar flares that scientists now classify as either M Class or the larger X Class flares. The largest solar flare observed by modern equipment to date was a X-28 flare in November 2003 which spurted out a Coronal Mass Ejection at 8.2 Million km/h. This was estimated to be similar to the Carrington Event but luckily the burst missed Earth entirely.
[1] The East Coast Sand River is something we explored in Wild Extremes. It’s the movement of sand northward along the New South Wales and southern Queensland coastline
[2] There has been a stronger wind gust measured during a tornado which struck Kurnell in December 2015 with a wind speed measurement of 213 km/h but as we shall see, these aren’t accepted by the Bureau of Meteorology.
[3] I haven’t included the Mount Washington record of 1934 due to how the measurement was recorded.
[4] An F6 tornado wind speeds starts at 512 km/h
[i] McTanish et al. 2011. Wind erosion and land management in Australia during 1940-1949 and 2000-2009. Australia State of the Environment Report. 2011