Tuesday, January 26, 2010

The Naming of Tropical Cyclones

Photograph: HMAS "Arrow" lies wrecked in Darwin Harbour following tropical cyclone "Tracy" in December 1974. Image: Wikipedia Commons - click to enlarge

Whilst many of the famous tropical cyclones in Australia’s history are instantly recognised by the names they were given, such as Tracy, Althea and Trixie, some of our most intense cyclones were never named at all.

The reason for this is tied up in the history of the naming of cyclones in Australia, which is an interesting story in itself. Clement Wragge, the rather eccentric Queensland Government Meteorologist from 1887 to 1902, is thought to have been the first person in the world to name tropical cyclones.

He called them after letters from the Greek alphabet, figures from Greek and Roman mythology, feminine names and also the names of some of the politicians of the day, including Drake, Barton and Deakin. Wragge considered that both politicians and tropical cyclones were national disasters.

In 1902, the Member for Werriwa was the Honourable Mr. A.H.Conroy, who somehow had incurred Wragge’s displeasure because he featured in several cyclone warnings. These included “Conroy, looking nasty, is coming along the coast” and “Conroy, black and treacherous, is likely to cross the Southern District…”. Justifiably miffed, Conroy dismissed Wragge as “an advertising scientist”.

After Wragge had left the meteorological scene in 1908, the naming of tropical cyclones lapsed and was not resumed by the Bureau of Meteorology in Australia until 1963. Then only feminine names were employed, but after complaints that this practice was discriminatory, both male and female names were used from 1975 onwards.

As a result of all this, cyclones that occurred between 1908 and 1963 were generally not given a name and these included some major storms that created massive damage and considerable loss of life. A powerful cyclone devastated Mackay in January 1918, killing 30 people and destroying some 30% of the housing in the area. And in 1954 a cyclone struck the Gold Coast of Queensland with 26 people perishing and hundreds of houses destroyed in the general area. Neither of these cyclones was named.

Tropical cyclone "Ingrid" threatened the Queensland coastline during March 2005.

(NASA image) - click to enlarge

Today, the names of tropical cyclones come from a list maintained and updated by the Bureau of Meteorology according to quite a strict protocol.

This contains five main guidelines that are called the “Tropical cyclone naming policy” and these are:

* Tropical cyclone names in each list are alternate male and female

* Names of cyclones that have already significantly affected the Australian region cannot be used again – for example “Tracy”.

* If two or more cyclones are occurring simultaneously, similar sounding names (for example June & Jane) are avoided to minimise confusion

* Names should not be capable of being construed to subject the Bureau to criticism or ridicule (for example naming a sequence of cyclones after politicians)

* Lists of names are coordinated with neighbouring meteorological services to avoid duplication

These guidelines, together with the current list of names being used, can be found at


Tropical revolving storms – that we call tropical cyclones in Australia - are referred to as “hurricanes” in the USA and “typhoons” in much of Asia.

Hurricane derives from the South American Carib word “Hurican” meaning God of Evil, and typhoon originates from the Chinese “tai’fung” meaning Great Wind.

Reference: Australia’s Natural Disasters, Richard Whitaker (New Holland Publishers) 2005.

Friday, January 8, 2010

Heatwaves in Australia

There is no universally accepted definition of a “heatwave” so to a certain extent we can make up our own. A simple and easy to remember definition is the 5/5 rule – that is five days in a row where the maximum temperature is five or more degrees Celsius above average.

But academic definitions aside, one thing is eminently clear – heat waves are lethal happenings – in fact the most deadly of all meteorological extremes. Perhaps surprisingly, heat waves kill many more people each year than tropical cyclones, bushfires, thunderstorms and floods. Whenever there is a heat wave there is an immediate spike in community mortality, and from analysing the nature of the “spike” experts can estimate the associated death toll.

Australia has experienced numerous recorded heatwaves and some of the main events are listed here together with the estimated number of deaths recorded nationally:

* January 1908 - 246
* February 1921 - 147
* January 1927 - 130
* January 1939 - 438
* February 1959 - 105
* January 1973 - 26
* February 1981 - 15
* February 1993 - 17
* February 2004 - 12
* February 2009 - 374

The temperature profile of the Melbourne heatwave of January and February 2009. Note the three consecutive days over 43C in late January, followed by a record 46.4C on February 7. It is believed that 374 people died as a result. Melbourne's average maximum temperature for this time of the year is 26C.
Image: Wikipedia Commons.
(Click on image to enlarge)

These mortality numbers cannot be used to directly gauge the severity of heatwaves as the population and social habits of the day also play a role. The larger number or people around today will obviously produce a proportionate increase in mortality compared to the situation of say fifty years ago.

But on the other hand, people today have far more access to fans and air conditioning than their earlier counterparts. Direct comparisons are therefore difficult.

Australia’s southern capitals are all subject to heatwaves, including Perth, Adelaide, Melbourne, Canberra and Sydney, and these events are often accompanied by severe bushfires.

An interesting article appeared in the Melbourne Argus on Friday 19th January 1934 that contained some recollections of severe heatwaves in Melbourne over the years. The temperatures quoted are of course in the old Fahrenheit scale – 100 degrees Fahrenheit is approximately 38 degrees Celsius.

“A very good idea of the intense heat of Thursday (January 25th 1875) may be gathered from the fact that a gentleman of Soldiers Hill who thought it unnecessary to have a fire in the house to provide himself a meal utilised the suns rays to cook an omelette and the feat was successfully performed. He placed a school slate for a while out of doors then spread some butter upon it and breaking an egg thereon in a few minutes the egg was, perfectly cooked, as if done in the orthodox pan over a fire.

The Weather Bureau record on that day was 110.4 degrees, compared with 102.5 degrees yesterday. There were bush fires all over Victoria then; there were four days of intense heat in Melbourne, and it was reported that a stack of firewood had been ignited by the heat of the sun’s rays. As usual in a heat wave in those days the Yan Yean supply failed in most of the suburbs and water was carted in drays to Emerald Hill (South Melbourne) Richmond and

In 1883 the Hon. Ivo Bligh's cricket team was visiting Melbourne, on three days the temperature exceeded 100 degrees - twice it exceeded 104 degrees. Correspondents wrote to the newspapers of the odour of the filthy Elizabeth street drain-and the Yan Yean failed. For the next heat wave, in 1898, there was also an English team present and "Observer" wrote in his introduction to the account of the match, ' On every hand there were heard weary sighings for rain - rain by the inch even though Australia lost the cricket match because of it!” Almost the whole of Gippsland was ablaze. In Melbourne the horses of the Fire Brigade were exhausted and none could be found strong enough to take their places. Elms, planes, oaks, and willow trees withered in the parks in the first days of February.

In 1905 some persons walked through the streets of the city in bathing suits when 108.5 degrees was registered on two days in January - but bathing suits then were different. Amusements were postponed and labourers were forced to cease work.

The record heat wave in Melbourne, however, was in 1908 from January 15 to January 20, six days of “centuries" with a maximum of 109.1 degrees. There were many sudden deaths from heat-stroke; the heat hastened the deaths of many sick persons; there was a constant stream of ambulance wagons to the Melbourne Hospital, and the number of deaths was so abnormal that the Melbourne General Cemetery management was unable to keep pace with the demand for burials. The Yan Yean failed again though not so seriously. The heat was so intense in the Newport railway workshops that portions of it were closed. Schools postponed their opening after the Christmas holidays, stock and poultry died. Thousands of suburban residents left their homes and carried mattresses into the public parks. The tram and train services could not cope with the crowds who went to the beaches, and thousands were left stranded at St Kilda and Brighton beaches unable to obtain a foothold on the last trams and trains to their homes.

In February 1912 when there appeared the first report of a man and his wife having driven to the beach wearing bathing suits in a “motor landaulette”. Birds, beasts and even fish in the lakes dropped dead. Since then the heat and its effects have been more mild. A constable collapsed on Flinders Street station in 1922. In 1927 the most serious effect of 104.5 degrees in the shade after a run of hot weather, was that potatoes suffered from sunburn; two years ago a temperature of 108.9 degrees was registered at the Weather Bureau, and many persons suffered from heat-stroke”.

Even in modern Australian society with its air conditioning, fast communications and advanced medical practices, heat waves remain a summer menace, and with the experts predicting an increasing frequency, this is a menace that will probably get worse rather than better.