December 16, 2006

The north Atlantic hurricane season is over. A strong season had been forecast, culmination of a natural cycle possibly to be strengthened further by global warming.

But there were no Katrinas or Wilmas this year -- very nearly the opposite, with wave after African tropical wave torn apart by cross-shear before they could develop even into named storms, and almost all of those which did develop curving away harmlessly. On a local scale, the forecasting had erred sharply, and the N. Atlantic results held up as further evidence of the myth of global warming.

The rest of the world tells a very different story.

While Pacific storms tend on average to be larger and stronger than their north Atlantic cousins -- the 1979 typhoon Tip, the largest and strongest typhoon ever measured, was born in the mid-Pacific -- this year was exceptional even by Pacific standards. The Philippines were been hit by a record five typhoons of category 3 or greater (including four super typhoons), plus another at category 2. Durian, not even the net strongest of the six, had sustained windspeeds of over 230 kilometres per hour, and is believed to be the strongest yet recorded at that location.Typhoon Tip, largest and strongest typhoon ever known, compared to the size of the United States Fortunately it had weakened greatly when it crossed the South China Sea and went on to strike south Vietnam. Five typhoons in an average year, this year Vietnam absorbed nine; some of which crossed the Mekong Basin to also cause severe flooding in Laos and Cambodia: something which would usually happen once in every five years. Tropical cyclone Monica, with sustained windspeeds of over 280 kilometres per hour, became the most intense storm ever recorded in the south Pacific (and that in April, at the very tail end of Australia's typical hurricane season), and may yet turn out to have been even more intense than Tip. (Satellite measurements differ from those on the ground at Darwin, a city which still vividly remembers having almost been wiped off the map by Tracy on Christmas Day, 1974.) While Darwin this time was spared more than a glancing blow, the Queensland region was not as fortunate. Although significantly less powerful than Monica, Larry was still a category 4 when it struck, the most powerful cyclone to strike Queensland in at least a century.

Super typhoon Ioke by itself set several new records. Developing into a typhoon less than a day after storm organisation south of Hawaii, Ioke quickly built and held its strength to become not only the most powerful recorded typhoon in the central Pacific -- in fact, the first category 5 ever to form and fully develop in that region -- but also the longest-lived high-strength storm, never dipping below category 4 for over a week (with three separate intensifications into category 5), during which time it managed to cross the greater part of the Pacific Ocean -- and then back again as an extratropical storm. (The previous record-holder was 2004's Ivan.) Even after it had curved north, away from Japan, east of Russia's Kamchatka peninsula, to make an eventual "landfall" in Alaska as an extratropical storm with 8-metre waves and still an extremely damaging storm surge. The single saving grace was its avoidance of any significantly populated islands: allowing full evacuation or appropriate storm-sheltering of the few military bases in its path.

With the addition of Ioke, of the most powerful cyclones to have been observed in the eight cyclonic regions (~nine now, with the addition of the unique Catarina and the January storm in the south Atlantic, 2004), five have been in this decade, two more in the previous decade, and only Tip (west Pacific) dates from before 1997.

Light N. American hurricane landfall does not translate into a negligible cyclonic season: but we stand also at the peak of a natural cyclonic cycle. Whether global storms will keep getting stronger afterwards -- well, one hopes these possibilities (and what the human race can do to contain the consequences) can be considered and acted upon, independent of ideology.

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