La Nina could prolong Penrhyn drought and heatwave

Friday 22 January 2021 | Written by Emmanuel Samoglou | Published in National, Outer Islands

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La Nina could prolong Penrhyn drought and heatwave
Penrhyn continues to deal with water shortages. The remote island received an emergency shipment of 200,000 litres of water earlier this month. PHOTO: Kiri Ataera/Infrastructure Cook Islands 21011314.

Much of the country continues to grapple with the high temperatures from the summer, with the ongoing La Nina weather event believed to be responsible for drier weather in the north.

Forecasters expect little respite in the coming days for drought stricken Penrhyn, as more dry weather appears to be in store for the northern group atoll.

The Cook Islands Meteorological Service says the prospect for any rainfall on the island for the coming weekend is unlikely, while the rest of the north will see cloudy skies and a few passing showers.

Penrhyn saw brief rainfall this week, roughly 1mm according to the Meteorological Service, as drought conditions continue to persist.

The island received an emergency shipment of 200,000 litres of water last week, and government officials said a vessel is on standby in Rarotonga in case further shipments are needed.

An island government official has said the shipment would provide 40 days of water supplies for Penrhyn’s 250 residents.

In Rarotonga, the short-term weather forecast through the weekend includes partly cloudy weather with some showers.

Officials have attributed the uncharacteristically hot and dry weather up north to La Nina.

Affected by the trade winds, La Nina can cause different weather patterns for the northern group and the southern Cook Islands, said marine biologist Dr Teina Rongo.

“Part of the reason is because the Cook Islands extends from the north to the south, we spread about 5 degrees to about 23 degrees,” he said. “We stretch a long way, so of course you’re going to have varying climate conditions.”

Rongo said if trade winds are strong enough during a La Nina weather event, cool water from the far east of the Pacific will be pushed westward at the equator.

The cool water will typically bring drier conditions to the northern Cook Islands, he said.

The islands of the southern group however will typically see warmer weather with higher rainfall, as the cold water being pushed westward at the equator by the trade winds will push warmer waters south towards Rarotonga.

“During a La Nina event, the southern Cook Islands experiences warmer temperatures, and that warmer weather is often associated with more rainfall, but the opposite occurs in the north because they are closer to the equator,” said Rongo.

“We have historical data that shows this.”

Met Service director Arona Ngari said there will be a move from La Nina to a neutral phase before the country head into El Nino later this year, which is expected to bring the opposite conditions to that of La Nina for the northern and southern areas of the country.