Alia Huberman 29/03/2012
Cyclone Tracy – Anatomy of a Disaster
9.1 HSIE Australia’s Physical Environment Cyclone Tracy – Anatomy of a Disaster
9.1 HSIE Australia’s Physical Environment
What is a natural hazard?
A natural hazard is a situation in which the forces of nature combine to cause destruction. When a natural hazard impacts on a community causing wreckage of property and loss of life, it is called a natural disaster. One such devastating natural disaster – probably the most prominent one in Australian history – was the vicious tropical storm that hit Darwin in 1974, Cyclone Tracy. What is a cyclone?
A cyclone is a low pressure system, usually in the tropics, in which the air rises and surrounding air moves in, creating a twisting wind (cyclone means ‘twist’ in Greek) around it. In the Southern Hemisphere, cyclones circulate clockwise. The unstable weather conditions that are commonly found in or near such a cyclone will include rain or snow showers and breezy to windy conditions. Strong cyclones can cause thunderstorms and hail, and large and intense cyclones (such as the ones that hit Northern Australia, South East Asia and the Pacific Islands – these are called tropical cyclones)can produce very dangerous weather conditions like severe storms and can result in flooding. Cyclones are also called hurricanes or typhoons in other parts of the world. What causes cyclones?
Cyclones evolve over warm seas in the tropics and close to the Equator. Heated by the sun, air rises very quickly, which forms areas of low pressure. As the hot air rises, it becomes weighed down with moisture, causing it to condense into enormous thunderclouds. Cooler air is sucked in to fill the empty space that is left, but because of the perpetual spinning of the Earth on its axis, the air is angled inwards and then spirals upwards with acute force....