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Southern Hemisphere's strongest hurricane ever slams Australia

By: Dr. Jeff Masters, 3:09 PM GMT on April 24, 2006

Cyclone Monica slammed ashore as a Category 4 hurricane on a sparsely populated region of Australia's north coast today, missing major population centers and sparing that country from serious damage as was experienced in Cylone Larry earlier this season. For a time yesterday, Monica was the most intense tropical cyclone in Southern Hemisphere history--sustatained winds of 180 mph, and a central pressure of 879 mb. This is not far from the world record of 870 mb set in Super Typhoon Tip in 1979, and Monica ranks as the 14th most intense tropical cyclone in world history, and is tied with Cyclone Zoe of 2003 as the strongest Southern Hemisphere cyclone on record. Curiously, the Australian Bureau of Meteorology put Monica's pressure at 915 mb at the same time the Navy Research Lab was reporting 879 mb, so I'm not sure what Monica's final "official" pressure will be. Reliable records of cyclone intensity only go back to the mid-1980s in the Southern Hemisphere, but two of top five strongest hurricanes ever recorded there have occurred this year--Tropical Cyclone Glenda (898 mb) from March, and now Monica. What's really extraordinary about Monica is that she came so late in the season--tropical cyclone season is usually over by late April in the Southern Hemisphere.

Figure 1. Cyclone Monica at peak intensity at 0130 GMT April 24, 2006, the strongest storm in Southern Hemisphere history--180 mph sustatined winds, and a 879 mb pressure. Image credit: Navy Research Lab.

Monica has weakened considerably due to interaction with land, and now has a pressure of 935 mb estimated by the Australian Bureau of Meteorology. Monica probably came ashore as a Category 4 storm. Monica has missed major population centers, and has done little damage. The mining town of Nhulunbuy, on north-east Arnhem Land was thought to be in Monica's path, but the storm veered to the north, limiting the damage in the town to mostly downed trees. It now apears that Darwin, capital of the Northern Territory and a city of 110,000 inhabitants, will not receive a direct hit from Monica.In addition, Monica is expected to weaken as it interacts with the islands and peninsulas surrounging Darwin, so it is unlikely Monica will cause death and destruction similar to what Darwin experienced on Christmas Eve 1974, when Cyclone Tracy smashed the city with Category 4 force winds. Tracy was Australia's worst ever natural disaster. The storm killed at least 65, did over $4 billion in damage, destroyed 80% of Darwin's buildings, and left 20,000 homeless. The city was since rebuilt with stronger building codes.

Figure 2. Damage to Darwin, Australia, after the passage of Cyclone Tracy on Chrismas Eve, 1974. Photo courtesy of the National Archives of Australia.

Jeff Masters

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