Cyclones and hurricanes in the South Pacific

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What is the period of cyclones and hurricanes in Polynesia?

What is the hurricanes and cyclones season and which are the islands most at risk of tropical cyclones in the South Pacific?

Cyclones and tropical hurricanes in the Pacific Ocean typically form between 5 ° and 20 ° latitude from the equator, both north and south, their strength and energy deriving from the heat that is released during the condensation process of water vapor.

A tropical cyclone is formed when a tropical depression is intense enough to cause winds above 63 km per hour near its center. According to the current classification, cyclones are divided into 5 intensity classes (1, 2, 3, 4, 5). With winds blowing in the center of the cyclone, between 63 and 118 km per hour, the cyclone is classified as a tropical storm, these are classes 1, 2 and 3. The two most dangerous classes are 4 and 5, these are the two classes in which a tropical cyclone is classified as a hurricane, a cyclone becomes class 4 when the winds exceed 118 km per hour, class 5 is the most destructive, in this case the winds exceed 167 km per hour.

WHERE ARE THE CYCLONES AND HURRICANS IN THE PACIFIC?

In the vast area of the South Pacific, the period of tropical cyclones occurs in the months between November and April, in this huge expanse of ocean that goes from Australia to Easter Island there are on average about 8-10 tropical cyclones per year, all concentrated in the months indicated above. The highest cyclone frequency is found in the months from January to March. The area most likely to experience a tropical cyclone in the South Pacific is that of Vanuatu, New Caledonia, Fiji, Tonga, Niue and the islands of Wallis and Futuna.

While a little less frequent are cyclones in the area that goes from the Solomon Islands, the Samoa islands, the southern Cook Islands, to the Tuvalu. Even less likely are cyclones for the Society Islands, the Tuamotu Islands and the Austral Islands in French Polynesia, the Tokelau Islands and the Northern Cook Islands. Outside the area of tropical cyclones are the archipelagos of the Marquesas islands in French Polynesia, the Kiribati islands and the Easter island.

TABLE OF AVERAGE OF TROPICAL CYCLONES PER YEAR IN THE SOUTH PACIFIC ISLANDS

ARCHIPELAGO	Number of annual cyclones (average over the past 37 years)
VANUATU	3/2,8
NEW CALEDONIA	2,7/2,6
FIJI	2,5/2,4
TONGA	2,1/2
WALLIS AND FUTUNA	1,9/1,8
NIUE	1,8
SAMOA / AMERICAN SAMOA	1,6/1,3
SOUTHERN COOK ISLANDS	1,5/1,3
SOLOMON ISLANDS	1,4/1,0
TUVALU	1,2/1,1
NEW ZEALAND – NORTH ISLAND	1/0,9
TOKELAU	0,8/0,6
FRENCH POLYNESIA: SOCIETY ISLANDS	0,8/0,6
FRENCH POLYNESIA: AUSTRAL ISLANDS	0,8/0,5
NORTHERN COOK ISLANDS	0,8/0,4
FRENCH POLYNESIA: TUAMOTU ISLANDS	0,4/0,1
PITCAIRN	0,3/0,1
FRENCH POLYNESIA: MARQUESAS ISLANDS	0,1/0,0
KIRIBATI	0

Data: NIWA National Institute of Water and Atmospheric Research, New Zealand

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