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Downpour adds to record month for rain

Tuesday March 31, 2015 Written by Published in Weather

A massive downpour which pummelled Rarotonga on Friday evening brought 27.4 millimetres of rain between 7pm and midnight.

Total rainfall for the month has now reached a staggering 335mm, just under double the average rainfall for March.

Friday’s heavy torrential rain made visibility difficult for motorists and slowed traffic to a crawl. Many motorcyclists opted to abandon their machines and seek shelter during the intense downpour, which also caused surface flooding on roads around the island. 

Cook Islands Meteorological Service director Arona Ngari said a maximum of 11mm of rain per hour fell between 7pm and 8pm.

The rain, which was accompanied by heavy winds, was associated with a depression to the south of Rarotonga. However the the heavy rain had been unexpected and had ‘come from nowhere’ he said.

“We knew the depression was there, but didn’t expect it to deepen to that extent.”

A total of 21.1mm of rain fell in the 24 hours from midnight Friday to midnight Saturday, Ngari said.

One Rarotonga resident said tornadoes had been spotted in five areas about 100 to 200 metres off the coast in the area between Avana to Matavera, from midnight on Friday to 2am on Saturday. Ngari said the tornadoes, accompanied by fierce winds, would have been associated with a build-up of cumulonimbus cloud.

And if an awful lot of water seemed to fall on the island on Friday night, it pales in comparison with the period from midnight on March 4 to midnight on March 5, when 67mm of rain was recorded at the Nikao meteorological station.

The highest hourly rainfall rate was recorded on March 7, when 34.9mm fell in just one hour.

Cyclones are largely to blame for the huge amount of rain this month. Ngari says the ‘hyper-active’ cyclones which hit the middle part of the South Pacific region were responsible for pumping a large amount of moisture into the area.