Updated on March 13 : It is middle of March, with summer approaching Northern Hemisphere, but in the other half of the world, there are not one, not two, but four tropical cyclones.
The most intense of these four, is Cyclone Pam, whose maximum sustained winds have reached 160 mph northeast of Vanuatu on early Friday morning, it is likely to attain Super Cyclone status later in the day.
Meanwhile, Cyclone Olwyn is all set to make landfall in western Australia, Cyclone Nathan will be turning east in the Coral Sea, just north of Cairns in Australia and finally, there is a Tropical Storm Bavi east of Guam in the western Pacific Ocean.
Very Unusual?
It is quite common to have two tropical cyclones at the same time in the same basin, specially in the peak of the season. Three Cyclones at a time in the same basin is a rare phenomenon, but four simultaneous hurricanes has only happened twice in the Atlantic Basin that is why it is rarest of the rare!.
Last time it happened was in September 25 to 27, 1998. Hurricane Georges was moving to make a landfall on the Gulf Coast when Hurricanes Ivan, Jeanne and Karl meandered harmlessly in the central Atlantic Ocean.
In the only other instance of four hurricanes at the same time, it was on 22 August 1893, when four hurricanes were active in the Atlantic. One of these was the ‘killer Hurricane’ Sea Islands hurricane, which claimed about 2,000 lives in Georgia and South Carolina.
Unbelievably, there have been five active Atlantic tropical cyclones at one time, from September 11 to 12, 1971. As per records in the National Hurricane Center, not more than two were of hurricane strength at any given time.
When and where Cyclones form?
Cyclones generally form in warm waters in tropics. For Indian Ocean basin the most favourable period is September to November & then form March to May. However, November to April is the season for tropical cyclones in the southwest Pacific Ocean, and they can occur round the year in western North Pacific basin.
The necessary conditions for formation of Cyclones are:-
Sea Surface Temperature higher than 26.50C
Pre-existence of a tropical disturbance.
Wind shear should be minimal.
Potentially unstable Atmosphere
Abundance of moisture
Slightly away from Equator
Updated on March 12: As if twin cyclones Nathan and Pam were not bad enough for Australian region, a third cyclone has rapidly developed and has been named Oilwyn on the western coast. This storm is close to Exmouth and will gradually travel towards Perth.
Luckily for cricket enthusiasts no further matches are scheduled at Perth. Similarly, the other two cyclones are also not threatening any of the cricket world cup venues as most of the cricket grounds in Australia lie in southeastern parts of Australia. Cyclone Nathan will affect Cairns in north Queensland.
The most powerful of the three cyclones Pam has strengthened to a category four equivalent tropical cyclone with maximum sustained winds of 130 mph and is located 665 miles northeast of Fiji, according to the U.S. JTWC.
The cyclone is likely to intensify further in next 24 hours to a category five on Friday through Saturday. If this cyclone takes a south-southwestward track it will be dangerously close to the eastern islands of Vanuatu on Friday, where it can dump torrential rains with gale force winds. The republic of Vanuatu is a chain of islands nearly 1200 miles northeast of Brisbane with a total population of 2.5 lakhs.
Updated on March 11
Tropical Cyclone Pam has already developed in pacific, east of the Solomon Islands and is moving towards Fiji. It is intensifying at a rapid rate and it is expected to attain Category III status in next 24 hours. Cyclone Pam will slowly move southwards over the open waters of the South Pacific Ocean.
While landfall is not likely, gusty winds and rain will affect parts of Vanuatu and Fiji from Friday onwards. Cyclone Pam has the potential to reach category five status which is equivalent to a major hurricane. Pam will mainly cause power outages and flash flooding over land as its worst impact will be borne by open waters.
Meanwhile, a low pressure became more organized on Tuesday to the east of the Cape York Peninsula and is now named Tropical Cyclone Nathan. This tropical system will move westwards during the week lashing parts of the northern Queensland coastline with squalls and heavy rains before stagnating and moving eastwards and making landfall. This cyclone is expected to reach the equivalent of a Category 1 or 2 hurricane.
Heavy to very heavy downpours are likely, starting from south of Cairns northwards through Cape Melville where rainfall of 50-100 mm will be widespread with localized thundershowers causing amounts of 200 mm or more. While the gale force winds will be observed offshore, few isolated gusts can still cause enough damage to down tree branches and cutoff power lines from Wednesday till Friday.
Gradually, this low pressure area will move to the western coast of Australia, where it will meet a cluster of thunderstorms which will help it become better organized and develop it into category three tropical cyclone later this week, few hundred miles west of Broome.
A normal course southwards would bring the threat of strong winds and heavy rainfall to the coastline of Western Australia from Exmouth southwards to Perth. Threat of Floods is very much on the cards with this potential tropical storm, as rainfall amounts of 25-75 mm will be widespread. Gale winds will be limited to coastal areas near Exmouth, as wind strength would decrease when system will come in contact with coastline. Though the rains will have potential to cause floods, the rains will be otherwise beneficial in the long run as Perth and the adjoining region has only received a rainfall of 1 mm since February 4.