Wild weather hammers North Island

This tree in Great South Rd, Penrose, was one of several that fell across powerlines or roads. Picture / Martin Sykes

About 17,000 households were without power in the upper North Island after a storm left emergency service workers struggling with arcing powerlines, fallen trees, sinking yachts and trapped motorists.

The storm, which brought winds of up to 150km/h in central Auckland, left a trail of destruction as it moved down the country.

Emergency service workers were stretched to their limits, with extra staff called in to help in some areas.

Most destruction occurred between Mangawhai and South Auckland, with many 111 calls coming from people on the North Shore.

In the five hours from 1pm to 6pm police at the Northern Communications Centre received 157 calls about blocked roads and 88 calls about vehicle accidents.

The Fire Service received more than 250 weather-related emergency calls. By 3pm the deluge forced the Fire Communications Centre to prioritise calls, sending only one fire engine to each job unless it was a confirmed fire.

Fire Communications shift manager Jaron Phillips said many calls were about powerlines and trees falling on homes or roads.

Besides the car accidents few people were injured.

Dozens of calls were about lifting roof tiles and building panels.

In Auckland a chimney was blown off a roof and the windows of another building were blown out.

Strong winds pushed at least one truck off the Southern Motorway and tore several boats from their moorings in the Waitemata Harbour.

Coastguard staff based at the Auckland Marine Rescue Centre in Mechanics Bay watched as one yacht floated past their window just after midday.

A rescue vessel was sent to save the boat but it sank before help arrived.

Although Auckland took the heaviest battering, Northland, the Waikato, Coromandel and Bay of Plenty did not escape the bad weather.

There was a two-car accident on the Kopu-Hikuwai Rd in the Coromandel and the roof was lifted off a motel in Whakatane. The living-room windows were blown out of an elderly man's house in Ruakaka and roofs were lifted in Mangawhai.

Throughout the day about 37,000 residential customers experienced power cuts. Around 17,000 were still without power as night fell.

This morning, Vector's operations manager Graham Petrie said the company had managed to restore power to the majority of its 12,000 customers last night. However, two "pockets" - totalling around 150 households - were still without power this morning, he told National Radio.

Tracey Bridges at Powerco said at first light about 700 of its customers were still without power.

Powerco network manager Ross Dixon earlier said its network - which includes the Coromandel Peninsula and the Bay of Plenty - reported more than 100 faults.

"This storm is pretty widespread - it's massive - and the network is being peppered all over," he said.

Vector spokeswoman Charlene White last night said winds of up to 130km/h caused major problems to the network, which delivers power to parts of Auckland and Northland.

She said fault crews would work through the night to try to restore power to as many customers as possible. "It's the severity of the wind. We have a really strong network but [with] that kind of strength of wind, it's very hard to avoid power outages, especially in outer-lying areas."

Road accidents

At 12.20pm a truck crashed into the centre barrier just before the Lincoln Rd off-ramp on the Northwestern Motorway. The driver was cut from the truck and taken to Auckland City Hospital with serious injuries.

At 1.45pm a truck rolled on to its side in heavy winds on the Southern Motorway at Ramarama.

Half an hour later a truck and van collided just south of the Waiwera Bridge on State Highway 1, trapping one person and delaying motorists.

Trees and powerlines

Trees and powerlines came down throughout the Auckland region, blocking roads, hitting homes and causing electrical arcing.

In New Lynn fallen branches caused an explosion on a powerline and a lightning strike set trees on fire in Riverhead. Motorists and emergency services were delayed in several areas by the fallen debris.

Power cuts

Regions that experienced power cuts throughout the day included:

* Northland, including Wellsford and Warkworth.

* Auckland, including Helensville, Coatesville, New Lynn, Henderson, Piha, Northcote/Birkdale, Waiheke Island, Bucklands Beach, Whitford, Coromandel Peninsula and Thames Valley.

* Bay of Plenty, including Tauranga.

Traffic lights were out in several parts of Auckland City because of flooding and fallen powerlines.

Structural damage

Throughout Auckland roof tiles and sheets of iron came loose, sometimes flapping in the wind, sometimes crashing to the ground. A door blew out of a home in Hauraki, on the North Shore.

Firefighters had to secure a caravan that nearly blew over in Snells Beach and a chimney blew off a roof in Waiwera.

A water tanker rolled down a hill in Greenhithe and crashed into the side of a house and trees came down on several homes and buildings.

Flooding

Firefighters were called to flooding at several homes and at an apartment building in Remuera.

There was surface flooding in Warkworth, Orewa and the North Shore.

State Highway 25A closed because of flooding in the Karangahake Gorge.

Water rescues

Several boats came adrift in Auckland.

A yacht sank by the container terminal after coming off its mooring in huge seas and a runabout was seen floating out at sea.

Two people were tipped out of their dinghy after trying to secure a boat in Matheson Bay. They managed to make their way to a rock ledge and climb to safety.

Four people had to be rescued from Fisherman's Rock at Whangaparaoa after becoming trapped.

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HOW IT HAPPENED AND WHAT HAPPENS NEXT

Last week's high pressure system moved east on Monday, leaving a northerly flow that brought the tropical rain clouds and low pressure system that were lying in the Pacific Islands.

The low deepened yesterday, causing high winds, but will have weakened overnight as it moves further from where it formed.

"It's a normal summer rain pattern for the northern North Island," said MetService weather ambassador Bob McDavitt. "We get a day of wind and rain and then it's all gone."

Parts of Northland, Auckland, the Coromandel and the Bay of Plenty regions had 40mm to 60mm of rainfall by 7pm yesterday, with two to three times more than that in surrounding hills. These regions had from between one-third and one whole month's worth of rain in a single day.

Whangarei and Whitianga had 106mm of rain, Auckland Airport had 43mm, and Tauranga, where it was still raining by evening, had 66mm. The Auckland Skytower recorded an average wind speed of 130km/h, with the highest recording hitting 150km/h.

The main rain clouds are expected to move south, with overnight heavy rain expected for the southern Coromandel Peninsula, Bay of Plenty, Rotorua, near the Kaimai Ranges, and Gisborne north of Tologa Bay. Another low pressure system will bring heavy overnight rain to mountain ranges near Nelson and high winds to the flanks of Mt Taranaki.

Heavy rain is expected in the central to lower North Island today and the north of the South Island, with conditions easing.

Aucklanders can expect lighter showers and light winds.

- additional reporting Juliet Rowan, NZPA