Ex-cyclone Gita to split in two as it crosses the country overnight
Monday, 19 February 2018
Ex-cyclone Gita will split in two separate systems as it crosses the country overnight, the MetService says.
'It is technically splitting into two low pressure centres as it crosses the South Island today,' MetService meteorologist Ciaran Doolin said. 'It will split as it moves across the Southern Alps.'
But he said the split would not materially impact on the spread or strength of the storm. 'They have a tendency to split a little bit like this.'
The stronger of the two systems would cross the country and end up southeast of Banks Peninsula, Canterbury, Doolin said. 'This is the main system, which will mainly be affecting the east coast tomorrow. It will bring very strong southwest winds and heavy rain; the heaviest rain being overnight tonight,' he said.
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The weaker of the two, forming near Westland, would be 'very shallow' and would bring some rain as it moved over the north of the South Island.
Overnight, the heavy rain bands moved south, away from Nelson, Marlborough, isolated Kaikoura and Christchurch, towards Ashburton, Timaru, the Mackenzie Country and further south Dunedin and Southland were impacted. The West Coast continued to receive strong rain through the night.
Winds were strongest in the Wellington region and coast Wairarapa, with gusts more than 100kmh and steady gales above 80kmh at Mt Kaukau, the Rimutaka Summit and Cape Turnagain in Wairarapa. In the South Island the strongest winds were at the tip of Banks Penninsula, the Port Hills south of Christchurch and Kaikoura.
The storm, which already caused devastation in Tonga, brought heavy rain and forecasts of high winds to much of New Zealand on Tuesday, with its centre predicted to cross the country from Tuesday night.
Kaikōura faced isolation as heavy rain, slips, rock falls and swell dangers closed State Highway 1 in both directions and also the inland route, SH70, with huge waves picked to hit coastal areas as the storm intensifies.
Power outages were reported in the Wellington region - Pukerua Bay, north of Porirua, and Akatarawa, north of Upper Hutt - and in Kaikoura overnight. Power had been restored to all but less than 100 customers in the Akatarawa outage.
Overnight temperatures remained mild in the lower North Island and upper South Island but dipped into the low-teens in Kaikoura and Christchurch, then cooler moving south and inland, with Mid Dome in Northern Southland and the Crown Range in Central Otago sitting at just 1C at around 4.20am.
Niwa forecasting principal scientist Chris Brandolino said localised areas of the upper and eastern South Island, including Tasman, Marlborough and North Canterbury could see rainfall approaching or exceeding 200mm before the end of Wednesday.
Across the whole country, northerlies would strengthen and rise to gale strength, possibly severe gale. 'It's going to rise significantly from late afternoon through to evening,' MetService meteorologist Nick Zacher said.
Brandolino said in the nine hours from midnight Kaikōura had received 39mm of rain.
The total was the largest of any weather station monitored by the organisation, he said, and much more was expected.
Brandolino said both Kaikōura and Waiau were among towns that could see 200mm by the time the storm moved away.
'There's a real flooding and slips risk because of the heavy nature of the rain.'
There had been significant rainfall in the 12 hours to midday for the Wellington region, with 60mm accumulating in some areas, MetService said.
Meanwhile, the agency had upgraded its heavy rain watch to a full warning for Canterbury including Christchurch and the Banks Peninsula, the ranges of Westland and north Otago. The areas joined heavy rain warnings for Nelson and Buller, Marlborough including the Kaikōura Coast, and Wellington and Kapiti Coast.
Between 150mm to 200mm was expected to fall in the Canterbury High Country from 9am Tuesday, with 90mm to 120mm elsewhere on the plains and Westland ranges.
SCHOOLS CLOSED, EMERGENCY PREPARATIONS
Dozens of schools and kindergartens had closed or were closing early as high winds and torrential rain loomed.
The Department of Conservation (DOC) was warning visitors and trampers to the Abel Tasman National Park and the Heaphy Track to exercise extreme caution on Tuesday and Wednesday, due to extreme weather forecast by cyclone Gita.
Large swells and storm surges are predicted, with a high tide at around 1.15am on Wednesday morning.
Further down the South Island, Westland District Council activated its Emergency Operations Centre from 11am Tuesday, with the storm estimated to hit the area from 1pm.
Residents were urged to prepare for gale force southeast winds of up to 150kmh as the bad weather took hold.
Prepositioning of equipment and staff across the Westland district was underway, the district council said.
Buller District Mayor Garry Howard said, at 8am, 'we're just starting to see a bit more intensity as the storm starts approaching'.
Timaru District Council had decided to activate its emergency operations centre to deal with possible weather-related issues.
HEAVIEST RAINFALLS
Bell said as the storm approached 'the winds from the south east are going to strengthen and that's going to see rain into the Canterbury/Christchurch area.
'The heavy rain is expected from around midday, into the afternoon. And that's expected to continue into the early hours of the morning.'
'Kaikōura is going to be a bit in the firing line, and also north Canterbury with very strong south to south-easterly gales, gusting 120kmh in exposed places - that's more from this evening.'
Bell said the worst of the winds and heavy rain would move in as the former cyclone tracked across the upper South Island later on Tuesday.
'We are expecting the worst of it to be on the east Coast,' he said of the rain.
However, the Buller District had a heavy rain warning in place, with the possibility of up to 150mm falling within the 24 hours from 7am Tuesday.
'Rain has set in on the West Coast, especially in the north - around Hokitika. The rain has definitely set in there.'
In Christchurch, Mayor Lianne Dalziel declared a state of emergency about 2.40pm on Tuesday because of storm concerns.
In Taranaki, Civil Defence was warning people to be prepared with gales gusting up to 140kmh predicted.
Taranaki Civil Defence response manager Craig Campbell-Smart said weather in the region would ramp up in intensity about 3pm.
Winds of 120kmh were expected in exposed parts of Taranaki and up to 140kmh in South Taranaki.
'We're expecting some potential damage to houses, fences, trees, flying objects - it could be bad'.
CENTRE OF THE STORM
Gita's centre was on track to hit the upper South Island and glance the lower North Island from the northwest. It was expected to be approaching close to Farewell Spit and Westport by 7pm or 8pm on Tuesday.
'That's where the most intense winds are going to be occurring. We're expecting wind gusts approaching 140kmh, even 150kmh. That's going to be about from late afternoon onwards,' Zacher said.
The biggest seas would also be around the same time: 'The swell's going to rise to 6 metres, possibly 7m. Add on top of that the wind wave, and it could approach 9 - 10m for a combined wave.'
Waves wouldn't be that big onshore but there was a chance of coastal inundation from the Kapiti Coast south, and on the Kaikōura Coast. 'There's a decent risk of flooding along the coast.'
AIRPORTS EXPECT DISRUPTIONS
Air New Zealand has warned travellers to expect delays to their travel plans on Tuesday afternoon, especially those travelling to and from regional airports.
Air New Zealand flights were cancelled in and out of Wellington, Hokitika, Nelson, New Plymouth and Queenstown.
Flights are still operating into and out of Blenheim, Palmerston North and Kapiti Coast.
Additional flights have been scheduled between Wellington and Auckland on Wednesday.
'TREACHEROUS' DRIVING CONDITIONS
State Highway 1, north of Kaikōura, from Mangamaunu to Clarence had been closed to heavy rain on Tuesday, as was the section between Peketa and Goose Bay. Travellers could still reach Kaikōura through the Inland Road.
Councils up and down the country were urging residents to check the state of play.
New Zealand Transport Agency senior manager Neil Walker said driving conditions were likely to be treacherous in many affected areas.
'Driving in these conditions will be extremely difficult and roads may be closed at short notice for safety reasons, with the possibility of slips, rockfalls, flooding and coastal inundation,' he said.
The West Coast and Nelson would be particularly vulnerable to disruption given several roads are still being repaired after the significant damage sustained during ex-cyclone Fehi, Walker said.
SNOW FALLS
Some of New Zealand's skifields are reporting a dusting of snow as Ex-Cyclone Gita continues to bear down on New Zealand.
Cardrona Alpine Resort has posted an image on Instagram of snow at the South Island resort.
'Sooo Gita has officially hit… a few cms of snow already & more than 40cm predicted over the next 24 hours.'
The Mountain Safety Council has also posted that several regions of the South Island will have snow forecast down to 1000m.
WELLINGTON
MetService meteorologist Tom Bell said the steady drizzle was likely to continue in Wellington with no particular time for peak intensity. The city was unlikely to get the 24 hours of rain predicted - it would ease off in the afternoon as the system was drawn south.
'There may be a few showers returning tonight. Probably the main story for Wellington is the wind. We're expecting it to get pretty windy this afternoon,' Bell said.
Air New Zealand cancelled flights in and out of Wellington, Hokitika, Nelson, New Plymouth and Queenstown.
High winds were predicted to strike at around 7pm, with winds up to 130kmh.
Metlink said the city's rail network was 'running to timetable' but commuters should keep checking through the morning.
A Greater Wellington Regional Council spokesman said Metlink planned to operate all bus, train and ferry services on Tuesday and also Wednesday, but this could change.
Ferries in Wellington Harbour were due to operate as normal on Tuesday, but this could change later in the afternoon if the weather worsens.
The East-by-West Ferry was due to run as normal in Wellington. Cook Strait ferry company Bluebridge had not cancelled any sailings but said they were monitoring the weather closely.
Interislander said based on current forecasts it expected all passenger services to sail, but there could be weather-related delays, a spokesperson said.
Meanwhile, Wellington Airport had blankets and extra staff on standby for passengers who could be stranded overnight.
MARLBOROUGH
The Marlborough region has been issued with a rain and wind warning, with up to 200mm expected between 10am and 10pm Tuesday, and strong winds for 24 hours from 4pm Tuesday.
Civil Defence advised campers, trampers and boaties in the Marlborough Sounds to leave the area if possible, while hunters and trampers in the high country should also keep an eye on rapidly rising rivers.
Road closures from high river levels are possible at the Pelorus across SH6, Wakamarina Rd, Queen Charlotte track at Havelock, SH1 beside the Para Swamp and SH63 Wairau Valley.
NELSON
Some Nelson residents will be struck with a sinking feeling of deja vu as residents worst affected by ex-tropical cyclone Fehi in early February are door-knocked by council staff, advising them to stay with friends and families.
The transport agency plans to close Rocks Rd, part of SH6, three hours either side of high tide on Tuesday.
The Nelson and Buller area are forecast to be hit by 12 hours of rain, with up to 150mm of rain expected to accumulate west of Motueka, and lesser amounts elsewhere.
Civil Defence staff had been pre-deploying to the Golden Bay area in case Takaka Hill Rd was affected, and warned residents to plan for storm surges similar to those of Fehi.
'Waves generated by the storm are likely along the entire coast and may impact into properties recently flooded by the Fehi storm,' a spokesman said.
'Residents are asked to have emergency supplies and evacuation plans up to date.'
Strong winds lasting a day and a half from 3pm on Tuesday were also forecast to batter the region, with severe east and northeast gales bringing damaging gusts of 140kmh in exposed places.
Civil Defence said the winds could topple trees and make driving difficult.
CANTERBURY AND WEST COAST
Canterbury and the West Coast are expected to have 15 hours of rain, starting 1pm Tuesday, with 150mm to 200mm of rain expected over that period.
Christchurch Mayor Lianne Dalziel declared a state of emergency because of storm concerns about 2.50pm on Tuesday.
Christchurch city has not suspended any services, but asked anyone with rubbish collection services to avoid leaving their bins out overnight.
Civil Defence response teams were also heading out on Tuesday to door-knock Christchurch homes flooded in recent weather events, to make people aware of the storm and enable them to prepare.
On the West Coast rain had set in - especially in the north around Hokitika.
Buller District had a heavy rain warning in place, with the possibility of up to 150mm falling within the 24 hours from 7am Tuesday.
Westport Harbour was closed from 9pm on Monday as a safety precaution. It would be reassessed at 12pm on Wednesday.
Schools across the Buller and Grey districts were closed on Tuesday, and visitors to the coast were being asked to bunker down in campsites.
A West Coast Regional Council spokeswoman said residents should have emergency getaway kits on standby, and said the storm's effect was likely to be similar to Fehi.
All windows and doors should be secured, and curtains drawn to avoid breaking glass flying into living areas.
South Cantabrians were beginning to feel the effects of Cyclone Gita on Tuesday morning, with one primary school opting to close because of issues with storm water drains.
MetService meteorologist Ciaran Doolin said Timaru had seen 38.2 millimetres overnight.