Flooding surprises farmers, campers

Northland is on alert after a weather system which dropped a month’s worth of rain in one night over the top of the North Island continues to wreak havoc.

A severe thunderstorm watch has been issued for the region, with the chance of a small tornado hitting amid expected torrential downpours, hail and flash flooding.

The deluge has already caused flash flooding across parts of Waikato and Auckland, closing roads and cutting off the Coromandel Peninsula for a time, causing slips and cutting power to hundreds of homes.

People were stranded in cars and residents were being evacuated in the cut-off Coromandel township of Whiritoa. Nearby Whangamata residents were left with no phones, petrol or wastewater after torrential rain continued to hammer the beachside town. There were also reports of substantial flooding around Hikuai, Tairua and Pauanui.

Flooding cut off access to the entire Coromandel Peninsula early yesterday morning after a night of downpours closed accessible roads.

By 10am State Highway 25 from Kopu to Thames had reopened, allowing access through the western side of the peninsula.

Whangamata, on Coromandel’s east coast, had 60 per cent of its normal entire autumn rainfall in the past 24 hours.

In Auckland, two police officers had to abandon their car as it rapidly filled with water in pitch dark.

In the Hunua Ranges, two school camps were forced to evacuate after unprecedented levels of rainfall caused flash flooding and slips. Roads in the Kawakawa Bay and Clevedon areas were closed, and emergency services were working to clear them as quickly as possible.

Auckland Council relocated park campers to higher ground and closed five regional parks because of flooding.

Metservice said bursts of heavy rain across northern New Zealand were possible through to tomorrow and issued a severe thunderstorm warning for Northland.

Heavy showers and thunderstorms were expected in central and western parts, with a moderate risk of thunderstorms becoming severe. Downpours with rainfall rates of 25 to 40mm/hour are expected, as well as hail in excess of 20mm in diameter. There is also the chance of a small tornado making landfall, but showers are expected to ease by early evening.

Metservice also warned that driving conditions will be hazardous, and that large hail can cause significant damage to crops, glasshouses and vehicles.

Overall, the heaviest rainfall was likely to be in Auckland, the Coromandel Peninsula, Bay of Plenty and Gisborne north of Tolaga Bay.

Massive amounts of rain had fallen in the ranges of the Coromandel Peninsula, Metservice meteorologist Tom Adams said.

‘‘There have been some huge numbers.’’

There was at least 79mm of rain at Whitianga airport in the past 24 hours – about half a month’s worth, while some stations in the ranges recorded more than 200mm.

Because rain had not stopped, the rivers in the affected areas continued to rise.

Further north, Auckland Airport, which typically gets about 80mm over the month in March, received 44.6mm overnight.

A river passing through a farm near Camp Adair in the Hunua Ranges passed a 100-year flood mark, the owner said.

Geoff Pearson, the owner of Wairoa River Farm and Rockup Adventures, said his 180 acres had suffered ‘‘a lot of damage’’.

The river had flooded to its highest point in over 10 years and he had lost cattle and fencing.

Pearson said the volume of rain took him by surprise. He said his rain gauges topped out at 150mm and they were already full at midnight. ‘‘There’s some unhappy people. Right now it’s raining still – the river’s dropped about a metre but the flooding is still extensive.’’

Auckland suburbs around the Hunua ranges and Hauraki Gulf were the worst hit by the deluge, with up to 200mm of rain falling on the city overnight, Metservice forecaster Heath Gullery said.

Many properties in the Papakura, Kawakawa Bay, Beachlands and Maraetai areas were directly affected by flooding and Civil Defence was warning local roads could be closed or affected by slips. One house had been evacuated.

Civil Defence was warning people in flood-hit areas to avoid travelling if possible, with the occupants of two vehicles in Beachlands being rescued after trying to drive through floodwaters.