Cyclone Mahina

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

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 a 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]

In comparison tropical cyclone Tracy which devastated Darwin in 1974 had a central pressure of 950 hPa. 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

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][13] a depiction of the Crest of the Wave in the storm can be seen here.

A storm surge, variously reported as either 13 metres or 48 feet high, swept across Princess Charlotte Bay then inland for about 5 kilometres, destroying anything that was left of the Bathurst Bay pearling fleet along with the settlement. Eyewitness Constable J. M. Kenny reported that a 48 ft (14.6 m) storm surge swept over their camp at Barrow Point atop a 40 ft (12 m) high ridge and reached 3 miles (5 km) inland, the largest storm surge ever recorded. However Nott and Hayne^[14] reviewed the evidence for this. They modelled the surge based on the 914 hPa central pressure and found the surge should only have been 2 to 3m height. They also surveyed the area looking for wave cut scarps and deposits characteristic of storm events but found none higher than 5 m. Of the 48 ft surge they suggest the ground level cited may not be correct, or that terrestrial flooding was also involved.

The cyclone continued southwest over Cape York Peninsula, emerging over the Gulf of Carpentaria before doubling back and dissipating on 10 March.^[15]

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 up on the cliffs, however this need not indicate a surge of this height as Nott and Hayne ^[14] 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.^[16] The disaster is also commemorated in the Anglican church on Thursday Island.

See also

• List of disasters in Australia by death toll
• List of tropical cyclones

References

External links

• Natural disasters in Australia
• Australia's worst cyclone disasters - Queensland State Disaster Management Group
• How high was the storm surge from Tropical Cyclone Mahina? by Jonathan Nott, James Cook University, & Matthew Hayne, Australian Geological Survey Organisation
• Video: The 1899 Pearling fleet disaster - an account by Ian Townsend. Created as part of the Queensland Stories project, State Library of Queensland, Australia. (4 minutes; Windows Media Player, RealPlayer)