Australia, cyclone Ita

Severe Tropical Cyclone Ita Threatens Queensland’s Northern Coast

Current location: 149.3°E, 11.4°S, moving west at a forward speed of 19 km/h.
Current intensity: Wind gusts of 220 km/h near the center of the storm; its central pressure is 962 millibars.
Tropical cyclone warnings: A cyclone watch has been issued for a 600-km swath of the far northern coast of Queensland between Cape Grenville and Cairns, extending up to 200 km inland to areas including Kalinga, Laura, and Palmerville.
Distance to closest population center: 630 km northeast of Cooktown, Queensland.
Hazards: High winds, heavy rains, flash flooding.
As of the Australian Government Bureau of Meteorology (BOM) advisory issued on Wednesday April 9, 10 p.m. (Australian Eastern Standard Time [AEST]), Severe Tropical Cyclone Ita – classified as a Category 3 storm by the BOM – is located about 630 km northeast of Cooktown, Queensland. With wind gusts of 220 km/h near the center of the storm, Ita is the most severe cyclone to threaten Queensland since Tropical Cyclone Yasi of 2011, which caused serious damage to the region south of Cairns.

Current Conditions and Forecast Track
As reported in the BOM advisory issued on Wednesday, April 9 at 10 p.m. AEST (12 p.m. UTC), Severe Tropical Cyclone Ita is characterized by wind gusts of 220 km/h and a central pressure of 962 millibars. Currently moving west with a forward speed of 19 km/h toward Queensland’s Cape York peninsula, the storm is forecast to continue moving west-southwest, along the periphery of a high pressure system to the south, before turning south. Ita is expected to continue intensifying under weak vertical wind shear and sea surface temperatures greater than 28°C over the next few days. Ita is forecast to make landfall as a severe Category 4 tropical cyclone near Cape Melville during the late afternoon on Friday, April 11. There is, however, uncertainty in the location and timing of the landfall, which is associated with the strength and movement of the high pressure ridge located to the south.

Forecast Track of Severe Tropical Cyclone Ita (Source: Australia Bureau of Meteorology)

Exposure at Risk
At Category 3 or 4 wind speeds, damage is expected to be significant, particularly to older structures. Structural damage to houses and buildings may occur, especially to rooftops, while windows and cladding on engineered structures could be damaged by impact from debris. Many trees will likely be uprooted and snapped, blocking roadways or damaging homes and automobiles. However, strong building codes have been in place across north Queensland and northern Australia since the devastating effects of Tropical Cyclone Tracy in 1974. For those structures that have been built to code, the structural building practices and requirements set down by the code will help mitigate the effects of high winds and associated debris.

Fortunately, Ita is currently expected to make landfall along a sparsely populated stretch of the Queensland coast, which—more than codes—will serve to mitigate losses.

Possible Impacts on the Queensland Region
By late Thursday, April 10, Ita may inflict gale force winds (63-87 km/h) between Coen and Cooktown. On Friday, after the storm intensifies further, high winds are anticipated to threaten the far northern Queensland coast between Cape Grenville and Cairns, with the most destructive winds expected after 4 p.m. AEST (6 a.m. UTC).

Heavy rains are expected to begin in northern coastal portions of Queensland as early as Thursday night. In addition, by the time Ita makes landfall on Friday as a severe Category 4 tropical cyclone, sea level is anticipated to rise significantly above normal tide height between Cape Grenville and Cairns. This unusually high tide, coupled with the storm’s high winds and heavy rains, may result in damaging waves, strong currents, and flooding of low-lying areas. Flash flooding is also expected in the region due to heavy rain. The Australian Government Bureau of Meteorology advises residents in low-lying areas to take measures to mitigate the effects of possible flooding on their property, and be prepared to evacuate if necessary.

AIR will continue to monitor the storm and will provide updates as warranted.

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