The process of naming cyclones

Thursday, 13 April 2017

Evacuations, closures, road and air travel disruption - even before the storm hit.

Cyclones like Cook and Debbie aren't given human names because they're mother nature's children - there's a more practical reason.

Ex-cyclone Cook, which originated in the South Pacific, has made its way towards New Zealand this week.

The swirling weather system has brought heavy rain, wind and swells to the northeast of the North Island, adding to Auckland and Bay of Plenty's weather woes.

Cyclones are named from lists assigned to different regions around the globe. The names are in alphabetical order and alternate between male and female names.

But how did Cook come after Debbie - the cyclone that recently rocked Australia before heading to Aotearoa - in what's supposed to be an alphabetical naming system?

**READ MORE:

Cyclone Cook, which was named by Fiji's meteorological organisation, comes hot on the tail of Australia's Cyclone Debbie.

* Live: Cyclone Cook

* How the storm will affect you

* Photos: Cyclone Cook slams NZ with heavy rain, severe gales, flooding**

HOW DID CYCLONE NAMING BEGIN?

The World Meteorological Organisation (WMO) says meteorologists have been naming storms for years to help with quick identification in warning messages.

Names are easier to remember than numbers and technical terms and help media report on weather systems affecting the public.

Meteorologists say using human names helps to heighten interest and increase preparedness within the community.

'Experience shows that the use of short, distinctive given names in written as well as spoken communications is quicker and less subject to error than the older more cumbersome latitude-longitude identification methods,' WMO says.

It's important for cyclone names to be easy to understand when exchanging detailed information between weather stations around the world, coastal bases and ships.

WHY ARE THEY NAMED ALPHABETICALLY?

Initially, storms were given arbitrary names.

Then a storm that ripped the mast off a boat named Antje in the Atlantic in 1842 became known as Antje's storm. After that, people started using women's names for cyclones.

In order to make the naming system more efficient, meteorologists decided to run through a list of names arranged in alphabetical order.

At the start of each year, those naming the cyclones circle back to the letter 'A'.

HOW IS THE CYCLONE'S GENDER DECIDED?

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By the end of the 1900s, forecasters had started using male names for cyclones that originated in the Southern Hemisphere, according to WMO.

Since 1953, Atlantic tropical storms have been named from lists originated by the National Hurricane Center in the United States. The lists of cyclone names for all regions in the world are now maintained and updated by an international committee at WMO.

The original name lists featured only women's names but in 1979, men's names were introduced and they now alternate with the women's names.

Six lists are used in rotation for each region. The cyclone's name is drawn from one of the lists assigned to the region where it originated.

WHY DID COOK COME AFTER DEBBIE?

Cook originated in the South Pacific so its name was taken from one of the lists assigned to the Regional Specialised Meteorological Centre Nadi in Fiji.

Cook is the third name in the fourth (out of five) lists that is drawn from to name cyclones originating in the South Pacific - after Amos and Bart.

The reason Cook came after Debbie is because Debbie was named from one of the Australian Tropical Cyclone Warning Centre's lists.

Debbie was preceded by Australian cyclones Alfred, Blanche and Caleb this year.

The only time there is a change in the list is if a storm is so deadly or costly that the future use of its name on a different storm would be inappropriate for reasons of sensitivity.

If that occurs, then the offending name is stricken from the list during a WMO annual meeting and another name is selected to replace it.

Infamous storm names such as Haiyan (Philippines, 2013), Sandy (USA, 2012), Katrina (USA, 2005), Mitch (Honduras, 1998) and Tracy (Darwin, 1974) have all been taken off the lists.