Weather: Tasman residents told to brace for flooding, 250km/h wind gusts in Canterbury

RNZ News

5 hours ago

An active front is expected to lash the South Island on Thursday.
Photo:
MetService
The Tasman District Council is expecting rivers across the region to be running at high levels, warning residents to prepare for flooding.
Heavy rain, thunderstorms, gales and possible flooding is forecast for much of the South Island.
The Tasman District council said uncertainty about the forecast and possible thunderstorms meant people should plan for flooding.
Council hydrologists said 75 to 140mm of rain had already fallen in the Tasman ranges in the last 12 hours.
The Tākaka River and its tributaries and the Aorere River had peaked or were about to peak, all below annual flood flows.
High tide coincided with the Aorere River's peak flow, so people could expect road and surface flooding in Ferntown.
Another 200 to 300mm of rain was expected in Golden Bay over the next 26 hours, along with possible thunderstorms and localised flooding.
River's in the region's east including the Wakapuaka, Maitai, Wairoa/Waimea and upper Motueka were also expected to reach annual flood flows.
Between 15 to 45mm of rain had already been recorded across the eastern ranges, with a further 150 to 250mm expected.
The council said there was a good chance the wet weather could cause slips, particularly on State Highway 60 over the Tākaka Hill and State Highway 6 between Nelson and Marlborough.
MetService severe weather warnings cover most parts of the island, with orange rain warnings starting in the early hours of Thursday for the Tasman District northwest of Motueka, Buller, Nelson and Marlborough, excluding the Sounds.
Haast Pass is closed between Haast and Makarora because of a slip.
MetService meterologist Heather Keats said there was "pretty decent rainfall and strong winds come through the South Island overnight as expected".
Canterbury High Country experienced "massive" 250km/h wind gusts.
"But that's a very elevated site that's quite exposed."
Other sites saw 90km/h gusts while some areas also had 10mm to 20mm of rain hourly.
"At the moment everything's playing out as we expected as that really active front does start to track over the South Island."
Environment Canterbury issued a riverbed alert for five alpine rivers in the region after heavy rain overnight.
The regional council said flows were increasing in upper parts of the Rangitata, Rakaia, Waimakariri, Hurunui and Waiau-uha rivers.
Expect windy conditions in the South Island from Wednesday afternoon to Thursday morning, especially in high terrain as well as the foothills of Canterbury and Otago.
Gusts >100 km/h () will have the potential to cause power cuts, tree damage, and difficult driving conditions.
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The focus would then shift to central New Zealand with strong wind watches in place for Wellington and rain watches for Taranaki from tomorrow.
It would continue north to affect the whole of the North Island, Keats said.
The active rain band affecting the West Coast was expected to stall over the Tasman/Nelson area and then affect Wellington and Taranaki.
Wellington region has been upgraded to orange wind warning.
MetService said Mount Kaukau recorded wind speeds of up to 130 kilometres while winds around the Wellington Airport and Kelburn were closer to the hundred mark.
Wellington and Porirua councils said they were unaware of the wind causing any damage - Fire and Emergency were also yet to receive any callouts.
Flights and the Cook Strait ferries are also still running.
File photo. Marlborough Emergency Management will be monitoring the Wairau River.
Photo:
RNZ / Samantha Gee
The weather system had the potential to stall, delivering additional rainfall on Friday, leading to a more significant weather event, the council and Marlborough Emergency Management said in a statement on Wednesday.
An update would be issued by the middle of Thursday afternoon for Spring Creek township residents on the potential impact on the Wairau River, once the latest forecasts had been assessed, the council said.
Heavy rain warnings in place for the headwaters of the Canterbury and Otago lakes and rivers, the ranges of the Westland district and Fiordland north of Doubtful Sound have been lifted.
Intense rain
led to flash flooding in Nelson
last month, which saw mayor Nick Smith renew his call for a rain radar.
With school holidays looming, Keats said: "Sunday looks amazing" while ski fields would benefit from fresh snowfalls over the next few days.
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