Tropical Cyclone Ita Buffets Australia, But Worst-Case Scenario Averted

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A volunteer Coastguard member helps tie down a boat before Tropical Cyclone Ita makes landfall later in Port Douglas, Australia.

Image: Ian Hitchcock

By Andrew Freedman2014-04-11 16:24:20 UTC

Tropical Cyclone Ita, one of the most formidable storms to ever threaten Australia, crossed the coast of northern Queensland near Cape Flattery at about 10 p.m. local time on April 11. Fortunately for those affected by the storm, it made landfall in considerably weaker shape compared to its peak intensity as a high-end Category 4 storm on the U.S. Saffir-Simpson scale, and a Category 5 storm on the Australian scale, with wind gusts of close to 190 miles per hour.

At landfall, the storm had maximum sustained winds of about 100 miles per hour, with higher gusts. The storm is now moving south-southwest just inland, over higher terrain, making it prone to additional weakening.

A zoomed in look at the eye of Tropical Cyclone Ita several hours before it crossed over Australia.

It is forecast to produce heavy rains and gusty winds, along with storm surge flooding, all the way south to the tourist hot spot of Cairns, with some computer models projecting that the center of the storm may swing further eastward, which could allow the storm to maintain some of its strength over the ocean and bring more significant hazards to Cairns and the tourist resorts north of the city.

“There remains the small possibility that Ita could track south close to the coast tonight and maintain an intensity capable of generating wind gusts to 130 kilometres per hour in Cairns during Saturday,” said Australia’s Bureau of Meteorology (BOM) in an online storm discussion.

Cairns is one of the major gateways to the Great Barrier Reef, drawing tourists from around the world to dive and snorkel to encounter the area’s unique marine life.

The BOM said the storm underwent subtle changes in its eye wall, which is the strongest part of tropical cyclone, comprised of towering thunderstorms immediately surrounding the calm center of the storm. When Ita crossed the coast, its eye wall had formed two rings, or what meteorologists refer to as a "double eye wall structure."

When this happens, the maximum winds in the storm tend to decline, since some energy in the original, unified eye wall is reduced. Weather forecasters have difficulty anticipating such subtle changes in storm structure far ahead of time, including the development double eye wall structures, which are usually part of larger eye wall replacement cycles, during which the original eye wall weakens and is replaced, which results in temporary weakening before a storm strengthens again.

In Cyclone Ita's case, the storm's small size also made it more vulnerable to weakening, the BOM said. “The system should weaken below cyclone intensity overnight Saturday night although strong winds are possible about the coast.”

Cyclone warnings remain posted for areas from Cape Melville to Cardwell, including Cooktown, Port Douglas and Cairns. While the BOM is warning coastal residents in these areas to prepare for storm surge-related flooding, it is not forecasting a catastrophically high storm surge, which could have resulted if the storm came ashore at its peak intensity.

According to the Australian Broadcasting Corporation, or ABC, there were many reports of trees down and homes damaged in Cooktown as well as other areas closer to the storm center. About 30,000 people were evacuated from low-lying parts of Cairns in anticipation of storm surge flooding, ABC reported.

"It is roaring outside - it is becoming more and more constant and people lost a roof off their house in Helen Street - we just don't know until tomorrow," said Cook Shire mayor Peter Scott.

Tropical Cyclone Ita was not as intense as Cyclone Yasi was when it struck Queensland in 2011 near Innisfail. That storm was both larger and more intense than Ita, and it became the most expensive cyclone in Australian history.

Topics: australia, Climate, hurricane, Queensland, tropical cyclone, tropical cyclone Ita, US & World, World