Helicopters dropping supplies to isolated families in Gisborne have been grounded as the storm which wreaked havoc in Auckland tracks down the country.

The storm brought flash flooding, hailstones and record low temperatures for February as the mercury plunged to 5C.

It was at its most destructive in Mangwhai - where slips closed roads and flooding left 200 people stranded - and in Waihi Beach where tornadoes swept in from the ocean bringing down power lines and lifting a roof off a house.

Hawke’s Bay, still recovering from the devastating impact of Cyclone Gabrielle last week, is under an orange heavy rain warning until 5pm today. Meanwhile, Tairawhiti Civil Defence said the weather had grounded helicopter flights.

“If you’re one of the families who has been expecting us - we’re so sorry but you are at the forefront of our minds. As soon as the weather clears, hopefully this afternoon helicopters will be back in the air delivering supplies.”

Parts of Auckland, Northland and Coromandel saw more than 100mm of rain falling in less than six hours on Friday night - the third time in a month that the regions have been impacted by severe weather, leaving residents feeling anxious.

A house on Seaforth Rd in Waihi Beach damaged by a tornado this morning. Photo / Scott Hetherington

Fire and Emergency was swamped with calls as severe thunderstorms caused chaos across parts of Auckland. Several stranded motorists were rescued by a boat after multiple cars were trapped in floodwater at Dairy Flat. Police also began evacuating households in the area, while 14 people were trapped at a flooded Silverdale school, where six children were later rescued.

About 20 students and their parents have been stranded at a school in Northland overnight as heavy rain caused flooding. Kaiwaka School principal Sharlene McCormick told the Herald this morning they were all safe but it was “horrific and terrifying” for the community to go through the weather event again.

There is no current road access between Auckland and Northland due to a slip near State Highway 1/Otiroro Rd, Topuni and multiple road closures through Mangawhai, Waka Kotahi NZTA said in a statement. State Highway 1 north of Te Hana is closed due to “multiple slips”, virtually cutting off Northland and the Far North. A section of SH16 between Kaukapakapa and Wellsford is also closed.

A Northland council rain gauge just outside Mangawhai measured a record 342mm for the day, most of it after midday. Just south of Kaiwaka, more than 150mm was recorded inland of Mangawhai Heads.

One man travelling from Whangarei to Auckland got caught in Mangawhai in the intense floodwaters. “I’d been driving around for about four hours back and forth trying to find a way out but all roads are closed or washed out or blocked by slips or floods,” he said.

As he tried to navigate a route through, he came across a ute stuck in the floodwaters. “I was trying to find somewhere safe to park and came across the ute in the flood - he must have just gone in because the two guys were escaping out through the windows - a couple of guys must have been late teens or early 20s,” he said.

The scene near Mangawhai, where a ute was submerged and its occupant had to swim for his life. Photo / Supplied

MetService said some sites in Auckland had seen more than 100mm of rain in six hours and mayor Wayne Brown urged residents to remain vigilant. “We want to assure Aucklanders that Auckland Emergency Management is fully operational, and emergency responders are on standby to assist people across the region,” Brown said. “Earlier this evening, two emergency mobile alerts were issued to advise our most vulnerable communities of the heightened risk of slips and flooding from thunderstorms, and I have been in contact with the councillors in those wards.”

Communities in some of the worst-hit areas from Cyclone Gabrielle braced themselves during an anxious night as authorities warned of heavy rain, localised flooding and the potential to evacuate at short notice.

Dramatic photos showed huge swathes of Mangawhai underwater last night and placid streams transformed into raging torrents.

Auckland Emergency Management (AEM) warned people to remain vigilant and not wait for official instructions to evacuate if they felt their life or property was in immediate danger. “Listen to your gut instinct and go,” AEM duty controller Adam Maggs said.

AEM sent an emergency alert to residents in Hellensville, Upper Harbour, Te Atatū and Henderson Valley about 5.20pm warning of potential landslides and flash flooding. A similar alert was sent about 5.10pm for hard-hit Bethells Beach, Karekare, Muriwai and Piha.

Heavy rain, police said, had already resulted in roads being impacted by slips and flooding in Mangawhai, Mahurangi East, South Head, and Topuni last night.

A Northland council rain gauge just outside Mangawhai recorded 342mm for the day, most of it after midday, according to Hauraki Gulf Weather.

Parts of Auckland’s motorway network also began to flood yesterday, including the Northern Motorway and State Highway 18.

Thunderstorms were recorded between Orewa and Warkworth and 37mm of rain fell in just one hour from a nearby station at Folded Hill yesterday afternoon, MetService said.

Some Auckland sites saw more than 100mm of rain in six hours, with peak intensities of 40-78 mm in an hour for some places.

Niwa meteorologist Ben Noll said the rain could be attributed to a cold front moving north which had “stalled out” over Auckland.

“Auckland and Coromandel are certainly going to be under the gun here,” he said. “If this rain continues into the night, then that timing may feel a bit like deja vu, given the event we had a couple of weeks ago.”

While that didn’t mean this storm system would be a repeat of the historic January 27 Auckland deluge, caused by a subtropical low, Noll said it nonetheless came with red flags.

Auckland Transport (AT) said roads damaged during Cyclone Gabrielle and the Anniversary Weekend floods remain vulnerable to the impacts of further rain.

There were full closures in place for at least 25 roads across the Auckland region, and there was a risk of further closures depending on the severity of rainfall overnight.

About 500 homes and businesses remained without power across the Auckland region, as of midday yesterday, including people at its west coast beaches.

A bus stuck in flood water on Auckland's Great North Rd during the Anniversary Weekend floods.

Access to Karekare, Piha, Te Henga Bethells Beach, Muriwai, Anawhata, Huia, Little Huia and Whatipū remained compromised.

Further south, Hawke’s Bay Civil Defence Emergency group controller Ian Macdonald said an order was made to evacuate the devastated Esk Valley area as heavy rain was expected to batter the region.

Macdonald said forecasts were for 100-150mm to fall between Friday afternoon and Saturday morning in the ranges west of Napier.

The evacuations were a pre-emptive and conservative approach.

“I do not want to be rescuing people off the top of roofs at short notice and I think this is the best thing to do for their safety and our first responders.”

Teams of about 50 people from police and Fire and Emergency went door to door making sure everyone had received the emergency mobile alert. Duty Controller Neville Reilly said the teams found that most of the houses visited in the evacuation zone were already empty following last week’s cyclone.

Residents of another 26 houses evacuated voluntarily this afternoon. Civil defence centres are open in Napier, Flaxmere and Pōrangahau to accommodate anyone who is not able to stay with whanau or friends and a centre is ready to open in Waipawa if needed overnight.

Roadblocks have also been set up around the evacuated area, to ensure properties are secure from looters.

The NZ Defence Force was evacuating people from Esk Valley in anticipation of heavy rain. Photo / Paul Taylor

Macdonald also pushed back against a Weekend Herald question that yesterday’s early evacuation order for Esk Valley came after the previous alert during Cyclone Gabrielle was too late for residents, some of whom said they did not get notice to leave until 5am as floodwaters were already raging.

“That was a completely different event,” he said. “That was very short notice, the amount of rain that we got was well above what was originally forecast. We’ve [now] got some warning, we’ve known about this for the last day and a half.”

Emergency services and the NZDF were sweeping through Esk Valley yesterday to ensure everyone, including roading contractors, left.

Macdonald wasn’t sure how many people required evacuating but estimated there were about 30 to 40 houses along with workers.

“We actually don’t know a lot about the [Esk] River at the moment because of all of the silt. So the behaviour of the river to even this sort of rain is why we are taking a conservative approach.”

Residents and contractors were evacuated from Esk Valley near Napier as heavy rain threatened to flood the area. Photo / Paul Taylor

Another bout of heavy rainfall was also likely to “remobilise” vast masses of flood waste left carpeting low-lying areas of the East Coast, associate professor of geology at the University of Auckland Martin Brook said.

Macdonald said he hoped people would be able to return to Esk Valley today to continue the clean-up, dependent on the weather conditions.

In Eskdale and nearby Bay View, 78 properties have already been assessed for damage after the cyclone and 23 were given a red sticker to signify they were uninhabitable. Some 53 were yellow-stickered, an indication of moderate damage or a reason to restrict access, and two white, meaning no significant damage.

Across the Hastings District, the number grew to 803 assessed properties and 78 red stickers, 643 yellow and 82 white.

Macdonald said Civil Defence would also be keeping a “close eye” on those areas where stopbanks had been compromised by the cyclone.

A bridge over the Tutaekuri River near Napier on February 16. Photo / Mark Mitchell

Modelling suggested there should not be any further impacts on the remaining bridges still linking Napier and Hastings, he said.

Hastings Mayor Sandra Hazlehurst said she was concerned for “our most vulnerable” Esk Valley.

“Our community is traumatised, they’ve seen a lot. They’ve been through a huge cyclone, a huge event that they’ve never seen in Hawke’s Bay in their lifetime.

“There are people out there feeling nervous and vulnerable.”

Cyclone Gabrielle wreaked havoc across parts of the North Island - including Esk Valley near Napier. Photo / George Heard

Frances Oliver, a clinical psychologist at Te Whatu Ora, said people would be feeling what had come to be known as “rain anxiety”.

“We are hearing from our communities that our children and young people are particularly affected at this time,” she said. “This will remind them of the events of last week.”

Gisborne Mayor Rehette Stoltz said teams in her district were keeping an eye on the weather and were concerned about more flooding on an already fragile roading network.

“We don’t need this,” Stoltz said.

Heavy downpours last night in Napier and Hastings had already caused surface flooding on several roads. About 2000 Hastings properties briefly lost power.

Hawke’s Bay’s heavy rain warning continues until 10am today and the thunderstorm watch until noon. Showers are expected to continue in the afternoon.

Gisborne’s heavy rain warning is due to expire at 4am but downpours and thunderstorms are possible throughout the day.

Auckland’s heavy rain watch is due to end at 6am today. The forecast is for early showers, possibly heavy, before the inclement weather eases up in the afternoon.