How Was Cyclone Tracy Formed?

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Cyclone Tracy developed as a tropical low-pressure system in the Arafura Sea between Australia and New Guinea on Dec. 20, 1974. The low was 300 miles away from Darwin in Australia’s Northern Territory. Cyclone Tracy killed 71 people, caused 650 injuries and destroyed 80 percent of the buildings in Darwin. As of July 2014, this storm is the deadliest in Australian history since modern record-keeping began.

Within a day of forming, weather forecasters noticed more development in the storm. Cyclone Tracy became a named storm Dec. 21 when it was 124 miles away from Cape Don. The shallow waters of the Timor Sea were very warm and caused the storm to intensify into a Category 3 storm by the time the cyclone made landfall on Christmas Eve.

A previous cyclone earlier in December 1974 bypassed northern Australia completely despite early warnings to the contrary. The University of Rhode Island asserts Cyclone Selma’s false alarm may have made residents complacent when warnings for Cyclone Tracy were issued. When the compact storm struck Darwin, its ferocity was intense. Surprised residents saw wind speeds go from a slight breeze to gale force in just 5 hours.

Darwin, with a population of 47,000 at the time, was decimated. There were 41,000 people left homeless and more than 35,000 evacuated after the storm. Every tree in the city was either uprooted or left bare by Cyclone Tracy. The storm was the most compact cyclone for its intensity ever recorded until Tropical Storm Marco in 2008.