Cyclone Mahina

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Cyclone Mahina
Category 5 severe tropical cyclone (Aus. scale)
Formed Unknown
Dissipated 5 March 1899 (1899-03-06)
Highest winds 10-minute sustained: 205 km/h (125 mph)
Lowest pressure 914 mbar (hPa); 26.99 inHg
(Lowest recorded pressure[1])
Fatalities 400-410
Areas affected Far North Queensland, Australia
Part of the Pre-1970 Southern Hemisphere tropical cyclone seasons

Cyclone Mahina struck Bathurst Bay, Australia and the surrounding region with a devastating storm surge on 4 March 1899, killing over 400 people, the largest death toll of any natural disaster in Australian history.[2][3]

Intensity[edit]

Tropical cyclone Mahina hit on 4 March 1899. It was a Category 5 cyclone, the most powerful of the tropical cyclone severity categories. In addition, Mahina was perhaps one of the most intense cyclones ever observed in the Southern Hemisphere and almost certainly the most intense cyclone ever observed off the East Coast of Australia in recorded history. Mahina was named by Government Meteorologist for Queensland Clement Wragge, a pioneer of naming such storms.

Such storms are extremely rare. Two other supercyclones (category 4 or 5) in the first half of the 19th century have been identified from their effects on the Great Barrier Reef and the Gulf of Carpentaria. This same research shows that such supercyclones occur on average in the region only every 200 to 300 years.[4]

Contemporary reports vary considerably in the reported lowest barometric pressures. The pressure recorded on the schooner Olive are reasonably consistent in showing the lowest pressure recorded on her: 29.60 to 29.10 [5] or between 29.00 and 29.10 inches [6] A further variant was "during the lull in the hurricane the barometer on the Olive recorded 29.70 to 29.10" (no units are given).[7]

Most sources record the schooner Crest of the Wave observation as 27 inches. e.g.[8][9][10] More modern reports of an 18-inch observation on a vessel in the eye of Mahina seem to have no relationship to contemporary records.[11]

Whittingham [12] has accepted the 29.1 and 27 inches reports from the Olive and the Crest of the Wave respectively seemingly unaware of the discrepant reports. He has estimated the track of the cyclone from the damage reports, placing it directly over the position of the Crest of the Wave. The Olive was to the north and missed the centre. A pressure there of 29.1 is consistent with that of the Crest of the Wave of 27 given the separation. He calculates the centre pressure, standardised for temperature, as 914 mb (hPa).[12]

Nott et al in a 2014 study found that the lowest pressure may have been around 880 hPa (mb) based upon GCOM2D modeling of meteorological variables needed to induce the potentially world record setting surge height of 13 metres (43 ft). This closely matches new evidence on storm depositions and accounts that Porter actually reported to two other captains and in a letter to his parents a reading of 26 inHg (880 hPa). The report of 27 inHg (910 hPa) was apparently thirdhand, was considered not necessarily reliable and the measurement may have been made five hours prior to passage of the eye.[13]

In comparison tropical cyclone Tracy which devastated Darwin in 1974 had a central pressure of 950 hPa (mb). Barometric pressure this low at mean sea level is also a likely cause and strong indicator of why cyclone Mahina created such an intense, phenomenal and claimed world record height storm surge of the likes not seen since.

Impact[edit]

Within an hour, the Thursday Island based pearling fleet anchored in the bay or nearby, was either driven onto the shore or onto the Great Barrier Reef or sunk at their anchorages. Four schooners and the manned Channel Rock lightship were lost. A further two schooners were wrecked but later refloated. Of the luggers, 54 were lost and a further 12 were wrecked but refloated. Over 30 survivors of the wrecked vessels were later rescued from the shore however over 307 were killed, mostly immigrant non-European crew members.[12][14] a depiction of the Crest of the Wave in the storm can be seen here.

A storm surge, variously reported as either 13 metres (43 ft), swept across Princess Charlotte Bay then inland for about 5 kilometres (3.1 mi), destroying anything that was left of the Bathurst Bay pearling fleet along with the settlement. Eyewitness Constable J. M. Kenny reported that a 48 feet (15 m) storm surge swept over their camp at Barrow Point atop a 40 feet (12 m) high ridge and reached 3 miles (4.8 km) inland, the largest storm surge ever recorded. However Nott and Hayne[15] reviewed the evidence for this. They modeled the surge based on the 914 hPa central pressure and found the surge should only have been 2 to 3 metres (6 ft 7 in to 9 ft 10 in) height. They also surveyed the area looking for wave cut scarps and deposits characteristic of storm events but found none higher than 5 metres (16 ft). Of the 48 ft (15 m) surge they suggest the ground level cited may not be correct, or that terrestrial flooding was also involved. A subsequent study by Nott et al considers this conclusion as possibly premature and questions the barometer reading as considered unreliable and as not representative of the lowest pressure. New evidence of exceptionally high storm surge and inundation was also examined.[13]

The cyclone continued southwest over Cape York Peninsula, emerging over the Gulf of Carpentaria before doubling back and dissipating on 10 March.[16]

Over 100 Indigenous Australians died, including some who were caught by the back surge and swept into the sea while trying to help shipwrecked men. Thousands of fish and some sharks and dolphins were found up to several kilometres inland and rocks were embedded in trees. On Flinders Island (Queensland) dolphins were found 15.2 metres (50 ft) up on the cliffs, however this need not indicate a surge of this height as Nott and Hayne[15] argue this was an exposed site and wave run up could readily explain this even within the more modest surge they have calculated.

A memorial stone to "The Pearlers" who were lost to the cyclone, naming 11 Europeans but only citing "over 300 coloured men" for the other seamen, was erected on Cape Melville.[17] The disaster is also commemorated in the Anglican church on Thursday Island.

See also[edit]

References[edit]

  1. ^ Nott, Jonathon; Hayne. Matthew, (12 June 2000). "How high was the storm surge from Tropical Cyclone Mahina?". Australian Journal of Emergency Management (Emergency Management Australia) (Autumn 2000): 11–13. 
  2. ^ "Natural Disasters". Australia's cultural portal. Retrieved 2009-02-11. 
  3. ^ "Australia's worst natural disasters". SBS World News Australia. Retrieved 2009-02-11. 
  4. ^ *Michael Allaby, Richard Garratt, Hurricanes, page 98, Infobase Publishing, 2003 ISBN 0816047952.
  5. ^ The Late Hurricane. The Advertiser (Adelaide, SA), p5, 14 March 1889. Available online at http://trove.nla.gov.au/ndp/del/article/29436768
  6. ^ The Late Hurricane The Brisbane Courier, p5, 14 March 1899. Available on line at http://trove.nla.gov.au/ndp/del/article/3689989
  7. ^ The Hurricane in the North. Kalgoorlie Western Argus, p22, 16 March 1899. Available on line at http://trove.nla.gov.au/ndp/del/article/32457780
  8. ^ The Queensland Hurricane. The Sydney Morning Herald, p5 13 March 1899. on line at http://trove.nla.gov.au/ndp/del/article/14204581
  9. ^ The Queensland Hurricane. South Australian Register, p6, 14 March 1899. Available on line at http://trove.nla.gov.au/ndp/del/article/54427620
  10. ^ Hurricane in the North. The Brisbane Courier, p8, 18 March 1899. Available on line at http://trove.nla.gov.au/ndp/del/article/3690283
  11. ^ The Cairns Post 20 November 2008, p17.
  12. ^ a b c Whittingham, H. E. 1958, The Bathurst Bay Hurricane and associated storm surge. Australian Meteorological Magazine 23: 14-36. Available on line at http://reg.bom.gov.au/amoj/docs/1958/whittingham2.pdf
  13. ^ a b Nott, Jonathan; C. Green; I. Townsend; J. Callaghan (2014). "The World Record Storm Surge and the Most Intense Southern Hemisphere Tropical Cyclone: New Evidence and Modeling". B. Am. Meteorol. Soc. 95 (5): 757–65. doi:10.1175/BAMS-D-12-00233.1. 
  14. ^ Pixley, N S, Pearlers of North Australia: the romantic story of the diving fleets. Journal of the Royal Historical Society of Queensland 9(3): 9-29. Available online at http://espace.library.uq.edu.au/eserv/UQ:209190/s00855804_1971_1972_9_3_9.pdf
  15. ^ a b Jonathan Nott and Matthew Hayne (2000). "How high was the storm surge from Tropical Cyclone Mahina? North Queensland, 1899" (PDF). Emergency Management Australia. Archived from the original on 25 June 2008. Retrieved 2008-08-11. 
  16. ^ Bathurst Bay, Qld: Cyclone (incl Storm Surge) Emergency Management Australia Disasters Database. Accessed 2008-12-29.
  17. ^ Outridge Monument http://monumentaustralia.org.au/monument_display.php?id=90490&image=0

External links[edit]