Cause+of+Cyclones

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__Description: What is a Cyclone:__
A **tropical cyclone** is an intense low pressure system that occurs in the summer months near northern Australia. They form over warm tropical waters. Tropical cyclones produce high winds and heavy rains

__Causes__
__**_**__
 * Tropical cyclone formation**
 * Cyclones that affect Australia usually form between November and April.
 * Tropical cyclones form over tropical waters with a surface temperature of 26 degrees Celsius or more.
 * These conditions are mostly found between the latitudes of 5 degrees and 30 degrees on both sides of the equator.
 * Warm water also warms the air, creating areas of intense low pressure.
 * This also encourages water to evaporate. The evaporated water molecules rise into the sky, eventually rising to a point where they condense into clouds. When many clouds form in one place in a way that could lead to the formation of a cyclone, the storm system is called a **tropical depression.** **_**
 * Due to cooler air pressing in from outside the storm system and the Coriolis effect, the cyclone begins to spin.
 * In the southern hemisphere, cyclones spin in a clockwise direction, while they spin in an anti-clockwise direction in the northern hemisphere. As the cyclone spins, it generates high winds and heavy rainfal**.**
 * Usually they die out when they move inland away from the water vapour, or out of the tropics away from the warmth**, depositing torrential** rain.
 * The energy released can be equivalent to 400 twenty-megatonne hydrogen bombs.


 * In order to aid people in identifying storms, tropical depressions and cyclones are given names to identify them. Tropical storms were once always named with women's names, but this changed in the 1970s.
 * Today, tropical storms are given both male and female names. These names are picked from a list of names.
 * Each storm is given the next name in alphabetical order on the list.

Environmental:

 * Some scientists believe that global climate change is leading to an increase in tropical cyclones and other tropical storms.
 * Since water temperature is rising in many parts of the ocean, more and stronger storms are forming.
 * This poses a significant hazard to many coastal areas affected by tropical cyclones.

> Cyclones as they cross the coast can cause **storm surges** through release of large amounts of heavy rains
 * **Torrential rain** released by a Cyclone as it passes over the land can also lead to **large scale flooding.**
 * that can lead to **large scale flooding of the shoreline and inland areas**, causing d**amage to beaches, harboursoss of lives.**
 * and leading to **loss of lives.**
 * **Very strong winds** that can reach from **150km to 380km per hour** can cause the **destruction of vegetation and the built environment** leading to the loss of life.

Economic/Social Impacts of Cyclone Tracy Christmas morning 1974

 * __Cyclone Tracy was so devastating because it passed directly over the City of Darwin early on Christmas morning 1974.__
 * __50 to 60% of building were damaged beyond repair.__
 * __ · The Damage bill was $4180million in today’s estimates__
 * __ · 35 000 people had to be evacuated__
 * __ · Few of these people had homes__
 * __ · There were no essential services__
 * __ · The threat of disease was a problem.__

**Civilian:**

 * __Many people acted heroically, working at great risk to rescue trapped people.__

Government:

 * __ · Government responded by providing Emergency services__
 * __ · Building of a new DARWIN__
 * __ · One that should be better able to withstand any future Tropical Cyclones.__
 * __New building codes were introduced to make buildings and homes more secure and strong.__

**Defences:**

 * T__he most important way that cities protect themselves from tropical cyclones is through detection systems.__
 * __In Australia, the Bureau of Meteorology identifies potentially dangerous cyclones and tracks them using weather stations on small islands and information from satellite pictures.__
 * __If a cyclone is deemed especially dangerous, a **cyclone warning** is issued in areas that might be affected.__
 * __These warnings are issued from three **Tropical Cyclone Warning Centres** (**TCWC**) located in Brisbane, Darwin and Perth. Cyclone warnings tell people how to prepare for the coming storm.__
 * __This can range from securing loose objects that might cause damage to evacuating the area until the storm has passed.__
 * _**