Rain closes state highway between Nelson and Blenheim

Thursday, 3 February 2022

The Nelson waterfront route has been closed around lunchtime as stormy weather and a high tide send waves across the highway.

Stormy weather and surface flooding closed State Highway 6 from Hira to the Rai Valley as widespread rain continues to drench the Nelson Tasman region.

The Tasman District west of Motueka is expected to bear the brunt of the forecast continued heavy rain with peak river levels expected on Friday and Saturday morning.

Metservice has placed the Tasman region West of Motueka under an orange alert for heavy rain, as well as the ranges to the east of Nelson.

The state highway through the ranges over the Whangamoa Saddle between Hira and Rai Valley was closed mid-afternoon on Thursday due to surface flooding, with a detour via St Arnaud.

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Rocks Rd was closed to all but heavy vehicles over high tide on Thursday due to high waves and heavy rainfall.

The Tasman District Council is urging caution near waterways and coastal areas.

Communications officer Tim O’Connell said there was likely to be some coastal erosion at peak high tides, but significant coastal inundation was not expected.

'We'd certainly discourage anyone from camping near rivers, especially in Golden Bay at the moment, where there's significant rainfall,' O'Connell said.

He said the heaviest rain was due on Friday night.

High river levels were expected to be centred in the Aorere Valley and to a lesser extent Tākaka catchments, with annual to five-year-flood levels projected.

The Tahunanui Beach foreshore took another pounding on Thursday as wild weather hit Nelson.

No major flooding was forecast in rivers east of the Richmond Ranges, though they would be higher than previously thought, he said. The council was cautious of unexpected high intensity rain which could push river levels higher than anticipated.

More than 100mm fell across Tasman district in the 24 hours up to Thursday morning and more rain is forecast. Rocks Rd was closed for a period on Thursday during high tide.

Beachgoer Angela Broecker was in the Tāhunnui Beach area at about 12:30 on Thursday and said that conditions on land weren’t too bad, with a bit of rain and wind and “some puddles but not flooding” on the road, the sea itself was quite rough.

“The ocean looked incredibly powerful washing away bits and bits of the beach. Although it looked like an outgoing tide by the time we went there,” she said.

“There were some people swimming, which I think was a very keen thing to do given the energy the waves were carrying today. At Abel Tasman statue carpark the water came up to the fence line, pushing debris and driftwood closer to the dune grassy area. It seems like the beach has lost more sand again.”

Extended periods of rain are forecast in the ranges west of Motueka, Rai Valley, Richmond and the Bryant Ranges, and the Nelson Lakes area from 10am on Thursday to 3am on Saturday.

The highest rainfall recorded in the 24 hours to Thursday morning was 268mm at Paradise Peak in the Haupiri range west of Tākaka, according to MetService.

Meteorologist Andrew James said a further 250 to 380mm of rain was expected to accumulate about the ranges west of Motueka, and 150 and 220mm near the coast.

Rocks Rd was still open to heavy vehicles, which could not take the alternative route, but high waves prevented smaller vehicles from traversing the waterfront.

In Rai Valley, Richmond and Bryant Ranges, and Nelson Lakes 200 to 300mm of rain was expected.

February is usually the driest month for the region, with an average of 80mm in Motueka from 1981 to 2010 according to NIWA data.

Nelson City Council group manager of infrastructure Alec Louverdis said the council and its contractors were “actively monitoring” roads, parks and reserves in order to clean up or repair any damage as soon as possible.

The council had been alerted to a minor slip on Cable Bay Rd and minor surface flooding in the Maitai Valley which closed the Maitai Valley Rd between Sharlands and the golf course.

“If the current orange weather alert warning remains the same, we will continue to monitor our network and assets closely as rainfall is expected to reach its peak late on Friday,” he said.

“Our teams are keeping a close watch on Monaco as we are expecting that some debris clean-up will be required on the receding tide.”

He said higher-than-usual tides were expected at around midnight and midday each day for the rest of the week, and people should be wary of potential surface flooding from seawater rising through the stormwater system.

Areas at risk included Wakatu Carpark, QEII Drive underpass, Paru Paru Rd, Vanguard St, Gloucester St and Tahaki St.

“Council has signage in place, but please be aware of this risk if you choose to park, drive, cycle or walk in these areas during the high tide. We also ask that people avoid walking in reserves until the weather improves,” he said.

“Please stay off mountainbike tracks and walking tracks as these can get very muddy and slippery. There is also the potential risk of falling trees and debris.”

Meanwhile, the West Coast is bracing for flooding with Westport a particular concern.