Yesterday’s downpour was the heaviest on Rarotonga in several years, the Meteorological Service says.
In just 12 hours early yesterday morning, the rainfall surpassed the average for an entire month.
Arona Ngari, the director of Cook Islands Meteorological Service, said the rain caused flooding in most low-lying areas.
Titikaveka, which is considered the wet side of the island, recorded 216mm of rain from 8pm to 8am. The maximum hourly downpour was 59.2 mm, recorded between 3 and 4am.
Nikao logged 121mm of rain from Wednesday 8pm to 8am yesterday. Half of that was recorded in just one hour, between 1 and 2am.
Ngari said the 12-hour rainfall figures they recorded yesterday surpassed the monthly average of 115mm for Rarotonga.
“The last time we recorded such heavy rain was about three to four years ago,” he said.
A further flash flooding warning remained in place for low-lying areas of the island last night.
Ngari said the heavy downpour was caused by “clashing of a trough line with a cold front which caused the formation of clouds that brings rain”.
It followed lightning and thunderstorms that lasted nearly an hour on Wednesday night.
Ngari said the lightning was caused by the formation of the cumulonimbus cloud before the clashing of the trough line and the cold front.
“The lightning was an indication that there was some heavy rain out at sea on Wednesday night.”
Ngari expects the weather to start clearing from later today to make way for a sunny weekend.
“The clashing of a trough line with cold fronts is not a normal feature, it doesn’t happen all the time. The system is expected to start moving away from us by Friday afternoon and we are expecting the weather to clear by the weekend.”
Ngari said thankfully, the downpour didn’t bring a cold spell like the one experienced in Rarotonga a week ago.
He said the temperature is expected to drop as low as 19C, but will remain above the 17C mark recorded last week.
“People should keep themselves dry, warm and safe during this weather and keep a lookout for updates from the Met Office.”