Here is a short YouTube video and photo montage I have put together of the January 5 storm surge and sea flood event in Kaiaua, Thames and the Thames Coast. Why it happened and some graphic footage of sea walls being overtopped, suburbs flooded, and roads wrecked.
I will do a more in-depth post but 2 points for now –
Waikato Regional Council say the water level was 2.8m – the highest in recent decades and close to the highest ever level of 3.0m in 1938 when the Hauraki Plains was extensively flooded from the sea
If the low-pressure system had tracked right over the Firth of Thames rather than off the west coast the sea level may have been another 15-20 cm higher still