Weather: Heavy rain, flooding and state of emergency in Nelson, West Coast, Buller; orange rain warnings for Auckland and Northland as 'atmospheric ri

WEATHER LATEST:• More than 200 homes in Nelson evacuated after Maitai River burst its banks• Nelson Tasman Civil Defence urges residents near the river from the Nile St Bridge to the Golf Course to evacuate immediately• Search and rescue teams helping people in flooded streets and suburbs, as NZDF patrol streets• The closure of State Highway 6 due to flooding means there is no direct link between Blenheim and Nelson• Nelson mayor describes it as a 'one-in-100-year event'.• Read about the extreme 'atmospheric river' behind this week's heavy rain here

More than 200 homes remain evacuated and a state of emergency remains in force in Nelson after rain and flooding caused by a severe "atmospheric river" has seen more than 300 mm of rain fall across the top of the South Island in 24 hours.

And there appears to be little respite for residents today, with more heavy rain and red weather warnings for Nelson, Buller and Westland. Aucklanders have also woken to heavy rain this morning, and orange warnings are in place for the region and Northland.

A state of emergency was declared in Nelson yesterday as residents were told to evacuate their homes immediately after the Maitai River breached its banks.

This morning the city's east remained closed with residents warned it was not yet safe to return home.

MetService said some parts of the Tasman District had recorded well over 300 mm of rain since midnight Wednesday and there was still more rain to fall.

In Buller evacuated residents woke to heartening news that the worst had not come to pass overnight with river levels falling. However, there was still concern that high tide later today could result in flooding. Those who stayed elsehere overnight were told this would be a major factor before the council could give the green light to return home.

The area experienced a month's worth of rainfall in just 15 hours, causing major flooding and slips. Nelson Mayor Rachel Reese described the flood as a "one-in-100-year event".

About 223 homes were evacuated in parts of Nelson, while video footage showed floodwaters beginning to encroach on the town centre.

Westport, Seddonville and Mokihinui residents were also warned the Buller River could peak this morning.

Nelson resident Sam Lagrutta told the Herald of the moment police officers were telling him and his sister they had just five minutes to evacuate and get to safety.

"I was running up the hill to grab a water pump, thinking I just needed to empty the front yard, and when I got to the bottom of the hill, police were there saying you have five minutes to get out.

"I literally just grabbed a carry-on bag and filled it with my passport, wallet, and anything important I could find."

Unfortunately, Lagrutta said the only important thing he couldn't locate were his cats, which he hoped were okay as he watched on from the hill, as the Maitai River's swollen water made its way up Mill St street towards his house.

He said that originally, evacuees could not leave the area due to slips and bridge closures.

"They told us to leave when we could, we all had to go up the hill because there was a slip on one exit and they had closed the bridge that was the other exit. "There was no way to get out of the area."

He described the situation as "frightening" and a "bit out of control".

He is yet to hear from authorities about when he might be allowed back into his home - today's heavy rain forecast does not bode well.

Nelson Tasman Civil Defence is urging anyone who lives near the river from the Nile St Bridge to the Waahi Taakaro Golf Club to evacuate.

"Stay with friends and family if you are able," the advice read. "If you have no safe place to go, head to the Saxton Stadium. Take pets, essential medications and warm clothing."

One elderly couple had to be rescued by Landsar from their residence on the Riverside. Rescue crews had to use a dinghy in order to reach the couple.

NZ Defence Force personnel have been patrolling evacuated areas overnight to keep an eye on properties.

Meanwhile, in the Buller emergency management team said Westport residents in Forbes, Coates and Gladstone streets should especially evacuate based on updated forecasts and modelling.

"The Buller River is likely to peak in Westport tomorrow morning (Thursday). As well, the tide will be slightly higher than it was in February," it said on its Facebook page.

"The combination of rainfall, river flows, tide and sea swell increase risk of surface flooding in areas that were affected at that time."

"As a precaution, we ask people to move in daylight to avoid the risk we would have to evacuate them in the dark, placing everyone including our emergency responders at risk."

As of last night, MetService has its highest red warnings for heavy rainfall for Buller, the Nelson region and Westland.

MetService meteorologist Ashlee Parkes said the heavy rain was expected to last until Friday. "There might be a slight easing overnight, but it won't be much."

Over the next 24 hours, the Nelson region is expected to see a further 400mm of rain on top of what has already fallen, which is over double the monthly average.

However, any respite for the region might be fleeting as more heavy rain is forecast for the weekend.

"We can't say with certainty if it will be better or worse than today's rain, but they will receive another good dumping," Parkes said.

The static atmospheric river which sits across the entire west side of New Zealand is the cause of the severe weather event.

The ranges northwest of Tasman had last night recorded 350mm, while 100mm had fallen at Rai Valley in Marlborough, 230mm at Franz Josef on the West Coast and 125mm at Hokitika.

Both Auckland and Northland have also received orange warnings for heavy rainfall from MetService.

Between 110mm to 140mm of rain is forecast in Auckland and Great Barrier Island in the 28 hours from 10pm last night until about 2am on Friday.

"Heavy rain may cause streams and rivers to rise rapidly. Surface flooding and slips are also possible and driving conditions may be hazardous," the weather authority said.

The same heavy rain warning is in place over Northland - for the 35 hours from 7pm tonight until 6am on Friday.

There are also expected to be severe gales in some areas, including Northland. Gusts of up to 120km/h in exposed places are expected from 9am tomorrow.

The closure of State Highway 6 due to flooding between Havelock and Hira means there is no direct link between Blenheim and Nelson. The alternative route is via SH63 and the Wairau Valley.

As the rain is set to continue, State Highway 6 between Blenheim and Nelson is likely to remain closed until Friday.

Below is a summary of road closures, slips and flooding across the region as at 6.30pm Wednesday:

• SH6 between Havelock and Hira - detour available via SH63, Saint Arnaud• SH63 between Inkerman and Anglesea streets - detour available via SH6 through Renwick• Para Rd from SH1 intersection• Centre Valley Rd - 520m from the start of the road, beyond the final residence• Ronga Rd, Rai Valley• Opouri Rd, Rai Valley• Wakamarina Rd - 13.3km in until approximately 1.5km before the end of the road• Stump Creek Rd - 170m to 200m, accessible from either end of Rapaura Rd• Port Underwood Rd between Waikawa and Robinhood Bays is closed to vehicles moe than 12.6m long• Upton Downs Rd, Seddon, is closed to heavy or wide vehicles from No 146• Awatere Valley Rd at Limestone Bridge

Slips

• Prices Rd, Havelock• North Bank Rd - several slips means the road is down to one lane• Kenepuru Rd - several additional slips today means the road is down to one lane in these locations• Port Underwood Rd - several additional slips today, including one before Karaka Point when travelling from Picton

Flooding

• SH1/Grove Rd between Nelson and Auckland streets• SH63 approximately 2km before the Korere-Tophouse Rd turnoff• SH63 approximately 2km after the Parsons Rd turnoff for around 700m• Old Renwick Rd between St Leonards Rd and Burnside Ave• Hawkesbury Rd from the start of the road to approximately 350m• Waihopai Valley Rd from 2.2km• Tapps Rd approximately 700m from the start• Wakamarina Rd• Hammerichs Rd• Centre Valley Rd• Rarangi Beach Rd• Kaituna-Tuamarina Rd• Croissilles-French Pass Rd between Okiwi Bay and Elaine Bay