Whether you call them hurricanes, tropical cyclones or typhoons, one thing is for sure, these are all tropical, intense and low-pressure systems that feature highly destructive winds.

In Australia, your summer is never complete without a cyclone. Every year, an average of 11 tropical cyclones form in Australian waters—four of which end up making a landfall.

So, what factors make a cyclone to occur and what are the impacts of cyclones?

Whether you call them hurricanes, tropical cyclones or typhoons, one thing is for sure, these are all tropical, intense and low-pressure systems that feature highly destructive winds.

What makes up a Cyclone?

The whirling superstorms usually develop in the warm waters of the tropical areas and mostly impact the northern Australian coast. However, they have the power to move down the coast or inland and cause far-reaching impacts as ex-tropical cyclones.

Some of the cyclones that have left behind a trail of damage include Debbie (2017) that caused floods whose effects spread into New South Wales, Oswald 2013 and Wanda (1974) which led to heavy flooding in Brisbane.

For any tropical cyclone to form, there are a few conditions that must exist:

  • Warm waters of at least 26.5 degrees Celsius
  • Low vertical shears
  • Rising humid air to give moisture to thunderstorm
  • At least 500km from the equator for a Coriolis effect to happen

The Coriolis effect refers to air that curves as it travels across the globe as the earth spins faster around the equator than around the poles.

When it comes to the Southern Hemisphere, the Coriolis effect occurs when winds are moved to the left so as to draw in air towards the tropical cyclone, and it’s then moved to the left, resulting in a clockwise whirling motion. And notably, typhoons and hurricanes in the northern hemisphere rotate in anticlockwise manner.

Vertical shear refers to a layer of air that moves at different speeds or direction to the layers of air atop it. An abundance of shears rips the storm apart, making it lose its momentum.


If a tropical cyclone forms, it feeds off all the moisture and heat produced, and spirals into a powerful natural event.

The intensity of a cyclone is measured in categories. Here in Australia, category five cyclones are considered the strongest, carrying the most damaging winds.

Normally, cyclones can be huge, spanning hundreds of kilometres in width with the strongest winds centred on the eye wall, which in turn surrounds the shrilly quiet ‘eye’ sitting at the core of the storm.

Note: If you find yourself in a cyclone and the strong wind stops abruptly, don’t leave. Chances are that you’re in the storm’s eye, which can take hours before passing over. Be sure to wait until all is clear before dashing for safety.

Other dangers include a storm surge—a situation where the tropical cyclone pushes the oceanic waters onto land, causing water to be thrown over six metres higher than the normal height.

Of all the naturally occurring events, storm surge carries the deadliest effects.

Rain also causes heavy floods before, during and after strong winds clear. Rainfall becomes more catastrophic when a storm travels slower or stops at a given area.

To enhance your safety and minimise the effects of storms or cyclones, it’s best to keep up with the latest warnings and ensure you have a plan to help you respond to any emergency, anytime, wherever you are.

For more information on tropical cyclones, contact Storm Assist and to see any active cyclones Australia wide, see Bureau of Meteorology Cyclone Watch.

The information contained in this article is of a general nature only. It does not take your specific needs, objectives or circumstances into consideration, and is not financial advice, legal advice or otherwise a recommendation to purchase any financial product or insurance policy. You should seek your own independent financial advice from a qualified financial and insurance adviser before making any financial decisions, and seek your own independent legal advice from a qualified solicitor before making any decisions of a legal nature.

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