Cyclones, typhoons, hurricanes: these extreme tropical storms often make headlines as they disrupt lives and leave devastation in their wake.
But what is the difference between them, and what causes them? Plus – why are storms given names?
What’s the difference?
Typhoons, cyclones and hurricanes are actually all technically the same thing: a tropical cyclone.
They are just referred to by different names based on where they form.
The term cyclone is used when the storms occur in the South Pacific and Indian Ocean.
They are referred to as typhoons when they appear in the Northwest Pacific.
And they are hurricanes when they appear in the North Atlantic, central North Pacific and eastern North Pacific.
What is a tropical cyclone?
A tropical cyclone is a rapidly rotating storm that begins over tropical oceans. It can vary in speed, size, and intensity.
The term tropical cyclone is used once a storm reaches maximum sustained winds of 74mph or higher.
They are measured by their winds, but they have other characteristics which can be severely damaging.
These include:
More than 1,900 disasters have been attributed to tropical cyclones worldwide since 1970, according to the World Meteorological Organisation, resulting in more than 790,000 deaths and $1.4trn of damages.
What causes a tropical cyclone?
They develop in tropical oceans at least 5 degree to 30 degree latitude north or south of the equator, where the sea temperature is at least 27C.
They can of course be devastating if they reach land, but they are important on Earth for transferring heat and energy between the equator and the poles.
The Met Office says the following conditions are needed for a tropical cyclone to form:
Why are storms given names?
Storms across the world are assigned names throughout the year to help make them easily identifiable for those affected by them.
Weather forecasters such as the Met Office say it means there is consistency in messages through the media and the government, making the public better placed to protect themselves, their property and businesses.
Every country is different, though many work together to name their storms for consistency, as they can hit multiple countries.
In Europe, for example, the UK, Ireland and the Netherlands work together as the western storm naming group.
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How are they named?
In the UK, the Met Office issues a new list of names which runs from early September to late August the following year, to coincide with the start of autumn and the end of summer, which is when they see the likelihood of low-pressure systems and with that, storms.
The list works its way down the alphabet – this year it started with Ashley, Bert, then Conall.
Every storm naming group has its own methods of choosing names, but the Met Office says it takes into account suggestions from the public which are sent in via email to [email protected] or through its online form, plus suggestions from its Ireland and Netherlands counterparts, Met Eireann and KNMI.
It says it has been choosing some of the more popular names from the public, as well as names which reflect diversity in the countries involved.
