general information
classification
cyclone warning system

school time
names of cyclones
on a personal note...

Cyclones

Cyclones can be both an exciting and an anxious time on the island. There is just one critical thing to get you through a cyclone - BE PREPARED! Although it will also help if you stay calm! The following information will tell you everything you need to know about cyclones to enable you to prepare yourself and your family so that you can comfortably survive this experience.

General information

The official cyclone season in Mauritius covers the period between 1 November and 15 May.

The Mauritius Meteorological Services are the best source of cyclone information. The information is frequently updated during the different stages of a cyclone. As soon as a cyclone approaches the vicinity of Mauritius and the outer islands, and gusts are expected to exceed 120 km/h, the warning system (see cyclone warning system) is put into effect by the Meteorological Services. A series of bulletins and a summary of the class of warning are designed to keep the public informed about the progress of the cyclone. Bulletins for each cyclone are issued at about six-hourly intervals and sometimes more often. Each bulletin is labelled first, second, third, etc - dated and timed.

A bulletin gives the:

  • Position, intensity and movement of the cyclone
  • Forecast of expected changes in the conditions of the wind and the sea
  • Expected time of commencement of specified wind speed and gust conditions.

The Mauritius Broadcasting Corporation (MBC) will broadcast cyclone news on the television and radio at the following times:


Morning
04h30 | 07h30 | 10h30

Afternoon
13h30 | 16h30

Evening
19h30 | 22h30 | 01h30

...and as the need arises. These bulletins will normally be in English, French, Hindustani and Creole.

As soon as a Class III warning is issued, MBC and Multi-Carrier (Mauritius) Ltd (MCML) will arrange to transmit the radio programs of Radio Maurice, including the bulletins, on all MBC FM radio frequencies and the following medium wave frequencies:

  • 575 KHz
  • 684 KHz
  • 819 KHz

In the event of a breakdown of all radio transmission facilities with a complete public and private radio blackout all over Mauritius, the principal means of communication with the public is on:

  • 1575 KHz medium wave.
Hotline numbers to phone before and during a cyclone (to hear the bulletins):
171
mobile phones
8996
landlines
 
150
Mauritius Telecom Call Centre if you cannot get connected to the above numbers.

These numbers (except for 150) are only in operation during cyclone warnings.

Helpful websites to follow the progress of the cyclone:


Classification of tropical cyclones in the south-west Indian Ocean


  Type   Description  
Zone of disturbed weather (or tropical disturbance) An area of low pressure relative to the surrounding region; the associated cloud masses are usually not well organized
  Tropical depression   A low-pressure system originating over tropical waters with some indications of cyclonic wind circulation. Winds circulate clockwise around low-pressure and cyclone systems in the southern hemisphere. Gusts are generally less than 89 km/h.  
  Moderate tropical storm   A low-pressure system originating over tropical waters with organized convection and definite cyclonic wind circulation. Estimated gusts range from 89 to 124 km/h.
 
  Severe tropical storm   A tropical storm in which the estimated wind gusts range from 125 to 165 km/h.  
  Tropical cyclone   A tropical storm in which the estimated wind gusts range from 166 to 233 km/h.  
  Intense tropical cyclone   A tropical storm in which the estimated wind gusts range from 234 to 299 km/h.

 
  Very intense tropical cyclone   A tropical storm in which estimated gusts exceed 300 km/h.  


The cyclone warning system (Mauritius and Rodrigues)

The warning system uses flags to indicate the different levels and is displayed at town halls, district councils, refugee centres, police stations and fisheries posts.

Name Code Description
Class I Issued 36 to 48 hours before the advent of cyclonic conditions.
Class II Issued so as to allow, as far as practicable, 12 hours of daylight before the occurrence of gusts of 120 km/h.
Class III Issued so as to allow, as far as practicable, 6 hours of daylight before the occurrence of gusts of 120 km/h.
Class IV Issued when gusts of 120 km/h have been recorded and are expected to continue to occur.
Termination Issued when there is no longer any appreciable danger of gusts exceeding 120 km/h.


Cyclones and school time

So, what happens during school time? Below is the warning system as issued by the Prime Minister's Office.

Class What to do?
Class I Normal school
Class II If a Class II warning is in force at the beginning of a school day, issued before classes begin, students should not go to school.
If a Class II warning is issued during school hours, classes will be dismissed without delay and the schools will be closed. As far as possible the Meteorological Services will issue Class II warnings on school days either at 04h10, 13h10 or 14h10
Class III No school.

Class IV No school.

Names of cyclones

The system of naming tropical cyclones was introduced in 1960, which is remembered as the year during which Mauritius was struck by cyclone Alix and also by cyclone Carol, the most devastating cyclone on record.

Madagascar, Reunion, Seychelles, Comoros and Mauritius use a common list of names for identifying tropical depressions. A list of the names for the current season is given on the Meteorological Services website.

Mauritius is responsible for naming depressions forming in the region lying between longitude 55ºE and 90ºE.

Madagascar is responsible for the region west of longitude 55ºE.

The Australian Bureau of Meteorology is responsible for the region east of 90ºE.

Whenever a cyclone moves from the Australian region of responsibility to that of Mauritius, it is given a hyphenated name comprising the names from both regions for a period of about twenty-four hours. Thereafter it is known by the Mauritian name.

On a personal note...

Now that you are armed with all the official information and you are high on adrenaline because of this strange phenomenon that is on its way towards you, it is time for personal action. For some people cyclones may be familiar, but for many others it may be their first encounter with a powerful storm like this, having only seen cyclones and hurricanes on television.

Below are some of the most important things for newcomers to the island to know about cyclones.

Preparation for a cyclone (before the cyclone reaches Class III)

Often we will only experience reduced effects if the cyclone passes nearby and not directly over the island. Be prepared for torrential rain for hours or days on end. Gusting wind can uproot trees, particularly ones with shallow roots and break branches off large trees. Objects not firmly secured will blow around and may cause damage, your building/windows may leak water into the house (depending on the direction of the wind and rain), and the electricity will probably go on and off. Without electricity you may not be able to flush toilets as the pump will not work - it is always useful to have a generator, which you must keep in working order and with a fuel supply. Ensure that you know beforehand its capacity, as naturally you cannot run all your appliances from one small generator and be prepared to only have possibly your fridge/freezer, water pump and some lights working.

The Central Electricity Board (CEB) may cut off the electricity supply at any time if it considers that circumstances render this necessary. Obviously, power may also go off because power lines have been blown down.

Class I and II cyclone warnings are still relatively safe for you to go out in, although rain might come down heavily and strong gusts of wind can start building up. The sea by the time of Class II is already turbulent, and the beautiful turquoise blue turns to a beige/brown mass of water, which is not safe to swim in. It is also the best time to get your boat out of the water. Be very practical here - take your cue from the local fishermen.

Important things to do in preparation for a cyclone:

  • Remove all furniture from the patio
  • Backwash the pool to empty it a bit as it will probably overflow
  • Park your car in a safe open area, not overhung by trees
  • Buy a battery-operated radio
  • Cut off any loose branches from trees around your house
  • Ensure that you have a silicone gun to seal leaks at doors and windows
  • Fill water buckets to flush the toilet (if you don't have a generator to run the pump)
  • Fasten down any loose objects which you can't bring into the house and which may blow around
  • Bring indoors or under shelter any treasured pot plants
  • Remember to take the satellite dish off
  • Make sure your pets are safely inside.

Important items that need to be in your house before, during and after a cyclone:

  • Drinking water
  • Mosquito coils
  • Non-perishables in case electricity is cut (unless you have a generator) - such as tinned food, dried food etc
  • Candles and a lighter (matches can get damp)
  • Torch and spare batteries
  • Extra fuel for the generator
  • Games that the children can play during the long hours where there might not be electricity and they are fed up of being cooped up in the house

It is worth considering that even if you do have a generator it is possible that it may malfunction or run out of fuel. Allow for the fact that you may be without mains electricity and a generator - how will you cook food (hopefully you have a gas cooker!), light your house and do many other things? Think about it and plan for it beforehand, rather than having to improvise if it happens in reality.

During a cyclone (From Class III until Termination)

Once the Class III warning comes into effect, everyone should leave work (apart from workers in essential areas) and make their way home. All final preparations should be made to your house.

During a cyclone, movement outside and the maintenance of services may become very difficult but officers employed on essential cyclone duties will do their utmost to maintain communications and services. All other people must remain inside their houses - do not venture outside for any reason.

During the passing of the eye of a cyclone, all possible warnings will be given to the public by police cars and other available means to ensure that the calm period while the eye of the cyclone is passing over the island is not mistaken for an end of the gusting winds.

The aftermath (what now?)

The end of cyclone warnings does not mean that the danger is over and that you can go out and return to normal life immediately. Rain and wind may continue for some time and there is now the risk of flooding and even flash floods. It is advisable to stay away from rivers, which may be very fast flowing and also the sea, which will remain rough for some time. Do not immediately venture out on foot or in your car, unless you really need to, as electricity cables may have come down, presenting a very real danger, and roads may be blocked by fallen trees and branches. If you do need to drive somewhere stick to main roads that you know, staying away from flooded roads if possible. Naturally, the after effects of a cyclone vary considerably depending on how severe the storm was and how close it passed to the island.

The website of the Mauritius Meteorological Services and The Cyclone and Torrential Rain Emergency Schemes document issued by the Prime Minister's Office were used to compile this text. Consult either of these sources directly for more detailed information on this topic.

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