Hawke's Bay's coast back to normal - aftershocks could derail that

High sea at Haumoana Beach. Photo / Warren Buckland

Cliverivercalmerafterwknd08.JPG Clive river looking normal, March 8. Photo / Paul Taylor

By Louise Gould

The coast is clear after Friday's severe earthquake near the Kermadec Islands triggered tsunami warnings and evacuations for Hawke's Bay – at least for now.

Hawke's Bay Civil Defence Emergency Management Group controller Ian Macdonald said until Saturday morning there was still activity around the Pacific and the world as a result of the 8.1-magnitude quake.

Macdonald advised the public to remain careful around the water up to 72 hours after a big earthquake and tsunami warning.

Clive River was flowing the wrong way and seemed abnormally high for low tide on Saturday, March 6. Photo / Screenshot

"Obviously, we're beyond that timeframe now, at the moment it should be safe," he said.

"The only concerns we have at the moment are around the aftershocks."

Macdonald said more aftershocks were still expected, and had the potential to generate abnormal surges in currents.

On Saturday the swell and water were still unusual, with video surfacing online of Clive River's water flow going in the opposite direction.

The Clive resident who took the video of the river, who wished to remain anonymous, said the river was very "full" for low tide.

Clive River looking calm and normal, March 8. Photo / Paul Taylor

Hawke's Bay Coastguard skipper Henry Van Tuel said when they went out on the water to train on Sunday, the swell was choppy but seemed "normal".

However, he said people still needed to be wary.

"The advice that we would always give is before you go in the water, check the forecast and if it doesn't look right then stay out," he said.

"Right now certainly, all our avocations are that it's back to normal."

Van Tuel said one of the coastguard members lives on a yacht in the marina in Napier.

"He noticed a little bit of change but nothing drastic," he said.

The coastguard skipper said the tide remained much higher than usual.

"There was probably an extra 20cm in it, which doesn't sound like a lot but it meant the water rose quite a bit higher than normal," Van Tuel said.

Macdonald said Hawke's Bay's CDEMG learnt some lessons from the events on March 5 and will be reviewing its protocols.

"This is a learning system; it will be better next time, that's the way that we treat it," he said.

"We need to further our education and communication around people being prepared, knowing which zone they live in if they live on the coast, and being able to make decisions themselves."

At the end of 2019, New Zealand upgraded its tsunami detection system, deploying a network of DART (Deep-ocean Assessment and Reporting of Tsunami) buoys.

Macdonald added that although the buoys speeded up the process of detection, for a local source tsunami this was difficult.

"This earthquake could've caused a local source tsunami." He said.

"The sea is basically a big bathtub and these waves just slosh around and deflect off things like coastlines and islands – which is why there is a lot of difficulty in giving definitive advice."