Lessons from Larry show cyclones can be ovalsNeroli Roocke, Wednesday June 26, 2013 - 14:44 EST
A study of an intense cyclone that hit the north Queensland coast in 2006 has revealed it was not a perfect circle and had a double eye wall.
Severe Tropical Cyclone Larry crossed the coast near Innisfail early on March 20 and between Babinda and Tully damage to infrastructure and crops was estimated to top $500 million.
Peter Otto was working at the Bureau of Meteorology's office in Brisbane at the time.
"I was forecasting for Cyclone Larry and also did a pretty comprehensive post-event inspection of the area afterwards and got to know and like the people and was challenged by one of the people that I met to try and help him understand the experiences that he had.
"There was also some important things we needed to learn about Larry in terms of its impact, its strength and its structure, so that we can better plan for the future."
Mr Otto says Cyclone Larry was small in size, about 200 kilometres across, but rated as the strongest event in that area for three generations.
He says his review showed Larry had a very complicated structure and that made accurate measurements of its wind speed difficult.
"Larry was affected by waves in the atmosphere just around its eye wall.
"It kind of had speed wobbles ... like a bad bicycle wheel it was moving around, but it was affected by these waves going around it that really did disturb it.
"These variations around its eye wall produced local areas that were much more intense in terms of winds and in terms of heavy rainfall.
"We are getting a better appreciation of this wave behaviour or speed wobbles within a cyclone ... and trying to help the community prepare for them.
"It affects coastal planning, it affects how many nails we put in the ceiling, where we put the buildings next to the coast."
Mr Otto says Cyclone Larry also had two eye walls which led to sea level rises in two different places.
He says recognising these factors will be important in the future when cyclone events are compared.
The study has been published by the United Nations-backed .
© ABC 2013
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