Heavy rain and snow cause havoc in South Island

Some South Island residents are being urged to evacuate, as heavy rains continue to batter the region.

Waimakariri District Council said Tuahiwi residents who live near the Cam River should stay with friends or family overnight, in case of further flooding following the 8pm high tide.

A Civil Defence Centre had been set up at the Riverside Church in Kaiapoi, where eight families had sought shelter.

Lower and Upper Selwyn Huts residents were being advised to evacuate if they were worried, as the Selwyn River continued to rise.

Selwyn District Council said a Civil Defence Centre was open at the Lincoln Event Centre, where two people were sheltering.

Canterbury Civil Defence controller Sean McCracken said crews were prepared to send out more evacuation notices if the rain intensified.

Road closures

The Ashburton River/Hakatere Bridge on State Highway 1 in Canterbury will close on Sunday night, after a weekend of downpours.

It will shut at 7pm to around 6am Monday, Waka Kotahi said on Sunday afternoon.

"The closure is precautionary given the build-up of flood debris around the bridge piers," Mark Pinner, system manager for Waka Kotahi Central South Island, said.

The water was not yet as high as it got in 2021's flood, which damaged the bridge, but a "cautious approach" was needed, Pinner said.

"If the river levels drop and concerns over debris lessen, the bridge may reopen later tonight or earlier tomorrow, however, we prefer people to be aware of the potential for the full overnight closure ahead of time."

Emergency vehicles would still be allowed across.

It follows the closure of local road bridges in Ashburton at 3pm.

SH77 between Thompsons Track and Pole Road, between Methven and Ashburton, was also closed, as was Geraldine to Fairlie SH79 at Middle Valley.

Small patches of flooding were reported on SH73 Springfield to Castle Hill, but it remained open. SH75 Banks Peninsula, Birdlings Flat to Cooptown was also still open, despite a small number of slips requiring stop/go management.

The Ashburton District Council is advising Mount Somers residents to boil water until further notice.

The council says water should be boiled for at least a minute before being used for drinking, cooking and hygiene.

Mayor Neil Brown says the council is likely to issue a boil water notice for Methven later this evening.

Some residents urged to evacuate

McCracken advised people not to wait for official directions to evacuate, if they felt it was necessary to leave their homes.

Waimakariri District Council said some properties had flooded and the council was responding on a case-by-case basis.

Fire and Emergency was pumping water from properties.

The region suffered widespread surface flooding overnight, with roads in Ohoka, Rangiora and Cust some of the worst affected.

Ashburton Deputy Mayor Liz McMillan said flooding was causing treacherous conditions on the roads.

"If you don't need to drive anywhere today, please just stay home. Be aware that just about every road will have some surface flooding. Some areas will be deeper than they look, so take extra care."

Flood signs were being put out and pumps and sucker trucks stationed in various locations across North Canterbury.

Drivers throughout North Canterbury were warned to stay off the roads, with fears melting snow could cause further flooding.

Several roads throughout the district were closed, including streets in Oxford and Sefton.

Waimakariri District Council said motorists should not drive through fords, even if they were dry. Melted snow flowing from the mountains could change conditions without warning, the council said.

Canterbury Regional Council said rivers were already up after heavy rain on Saturday night, and warned some might flood today as rain continues.

"Our main rivers of focus are the Eyre, Cust, Cam, Ohoka. Flows are increasing towards the design capacity of these rivers and Civil Defence Emergency Management groups are monitoring these areas carefully," the council said.

"The Ashley river is rising but is not expected to reach levels which threaten the flood protection scheme.

"The Okuku river may have localised out of river flooding, likely in the same areas that have seen these effects since 2021."

MetService issued orange heavy rain warnings for Canterbury and Eastern Marlborough south of Ward from Sunday morning until between 3am and 6am Monday.

The rain eased off Sunday morning, but the heaviest falls were expected between 3pm and midnight tonight, MetService said.

Eastern Marlborough and Canterbury about and north of Cheviot could expect another 70 to 100mm of rain during the warning period. The snow level was expected to rise to about 1000 metres late Sunday morning.

Another 60 to 90 mm of rain was expected to fall in Canterbury south of Cheviot. Snow was expected above 1000 metres in MacKenzie Basin from late this morning.

A heavy rain watch was in place for North Otago from Sunday morning until 3am Monday.

MetService said from Tuesday through to early Thursday, a cold showery west to southwest flow would affect New Zealand.

On Wednesday, southwest gales were possible about coastal parts of the North Island and these could become severe about Northland and Auckland. Later on Thursday and Friday, a ridge of high pressure was likely to spread across the country, according to MetService.

Several roads were closed in the South Island due to flooding and heavy snow.

The Canterbury region was socked in overnight, and it's expected to stay that way today.
This Rakaia Radar clip shows how consistent the rain has been.
Most locations in the region have recorded 40-60mm of rain between 8pm last night and 7am today, and more is expected. pic.twitter.com/TNu5BoqnSN

— MetService (@MetService) July 22, 2023

State Highway 77 was closed between Thompsons Track and the Pole Road intersection, due to flooding. State Highway 79 between Gudex Road and Maxwell Road was also closed.

Hip-height water

An Ashburton resident described flooding around his neighbourhood as hip height, after relentless rain overnight.

Tinwald resident Bailey Chambers said a nearby creek had caused flooding in his area.

"[The creek is] normally around 20 centimetres-odd deep and it's probably a good metre and a half or two metres to the top of the culvert.

"The neighbours' place, it's flooded all through the garage from what I can tell. This happened about six years ago to the day," Chambers said.

Kaiapoi-Woodend Deputy Mayor Neville Atkinson said from what he saw this morning, recent works appeared to have helped prevent more severe flooding.

"We've probably come through it better than we normally have. There's a lot of mitigation been put in recently and it seems to be working well," Atkinson said.

He advised residents to stay away from rivers and streams prone to overflowing.

Anyone who feels their home was at risk of being flooded should call 111 immediately.

Residents needing help to evacuate, or who live on a street where drains have overflowed, should contact their local council.

Sand bags are available from Rangiora New World and the Kaiapoi Football Club.