By Margaret Maccoll
There is no strong evidence of significant change in tropical activity due to climate change, cyclone expert Dr George Walker told attendees at the Tewantin U3A talk last Friday.
He said the warming of both sea water and the air above it at the same time is possibly the reason climate change has not affected cyclones.
The Adjunct Professor from James Cook University has studied cyclones since 1968 and led the investigation into Cyclone Tracy that devastated Darwin in Christmas 1974.
Dr Walker’s research has led to changes in building legislation that saw the introduction of increased measures to resist cyclonic winds.
He said when he visited Darwin following Cyclone Tracy, he expected media reports to have exaggerated the damage, but they hadn’t.
“The damage was incredible,” he said.
“Big buildings like schools that had been engineered survived reasonably well. The major damage was to houses. The failures were due to houses not being designed for internal pressures.”
Dr Walker said his major recommendation following the investigation was for houses to be engineered to the same criteria as larger buildings.
“It was radical at the time, but now it’s standard and it didn’t add a lot to costs.”
He said the changes required a major revision of the building code and with strong opposition from the building industry it took 20 years to implement.
Australia is now zoned to meet cyclonic wind speeds of varying intensity and requiring varying building requirements. Noosa is rated zone 2.
Dr Walker said houses built before 1980s if they haven’t been strengthened would not survive the winds of Cyclone Tracy.
Dr Walker said no cyclones in recent years had matched the destructive capabilities of the Mackay and Innisfail cyclones in 1918 or Cyclone Mahina in 1899 which claimed the lives of 300 Europeans and an unknown number of Aboriginals at Bathurst Bay, Cape York.
“We’ve been lucky,” he said. Part of that luck has been the timing in relation to the tides.
Both Cylcone Tracy and Cyclone Yasi, that hit Tully and Cardwell in 2011, made land at low tide which lessened the effects of their storm surges. The cyclone season in Queensland runs from November to April.
