Homes were destroyed and families forced to flee as scrub fires burned out of control in Canterbury.
Strong winds swept multiple blazes through dry fields and over roads south of Christchurch.
Selwyn District Mayor Kelvin Coe told the Herald last night that he had been told four homes were destroyed, but that number couldn't be confirmed.
The mayor said the fire started just to the north of Selwyn Rd.
"But it spread across Shands Rd, so it's gone downwind quite a considerable way."
Mr Coe said it wasn't known what caused the blaze.
Fire Service centre manager Ian Lynn said 10 people were evacuated in a "snap rescue" on Shands Rd by firefighters worried by the advancing flames.
"They got in fast and got out fast."
All the homes were near Prebbleton, on the southwest edge of the city.
Resources were stretched as firefighters battled another scrub fire on Waterloo Rd in Hornby.
A Shands Rd resident told of watching the inferno destroy everything in its path.
"It was very frightening," she said. "We saw this huge flame go up in the air... Just as we were watching, the fire crossed the road so quickly - it went through a block of land.
"It was on one side of the road then suddenly it was on the other."
The fire was about a kilometre away.
"It was just raging away and anything in its path exploded into flames... It spread so quickly. It's so hot and dry.
"I haven't ever seen a fire so big. It just reminded us of the bush fires in Australia."
A cordon was set up around the area as 10 fire trucks and helicopters with monsoon buckets battled the blaze.
Mother-of-three Sharon Honeywill raced home from Hornby when she heard about the Shands Rd fire.
She found the paddock behind her lifestyle block was ablaze, and gusting winds were kicking up smoke and flames.
"I felt pretty defenceless," Mrs Honeywill said.
"I was looking at my house, wanting to go and save anything personal, but when you've got your family there to think about, you could only sit there and watch the paddocks burning."
Last night, Mrs Honeywill did not know if her house had survived the fire.
Student Emily Spink was in tears when she came home to find her family home in the fire's path.
"Mum and dad are away, and they've left me in charge," she sobbed.
The Spink family's lifestyle block on Robinsons Rd was downwind from the flames.
While four helicopters filling monsoon buckets from swimming pools and irrigation tanks had contained the blaze, the roaring nor'west wind continued to fan it.
Farmer John Quinn leaned on a fencepost at the Springs Rd cordon and shook his head, as firefighters battled to stop the inferno spreading to his property.
"Bloody nor'wester," he said.
But Mr Quinn was philosophical.
"Being in the rural life, you get kicks in the guts all the time. You just have to start up again."
Fields had gone to seed, and coupled with a lack of spring rains and the relentless north-west winds, the fires were inevitable, he said.
"It's bloody dry."
Mr Quinn said the helicopters would bring the fires under control, even if it took a few days.
"It's got hold of the gorse, which has dry roots that go deep in the ground.
"They get it under control and then it sparks up again. We could be a while yet."
The temperature in Canterbury was almost 30C with a strong northwesterly wind - conditions incident controller Chris Hewitt described as "atrocious".
He told One News the winds were aggravating the situation.
"The ember flow from the original fire is causing us great concern."
Mayor Coe said a welfare centre was being set up at the Lincoln Events Centre where evacuated residents could spend the night.
Meanwhile, heavy rain lashed other parts of the South Island.
River and lake levels were continuing to rise in the Wakatipu, Wanaka, and Hawea lakes areas and flooding was expected in low-lying areas.
Several roads were closed by slips and washouts but all were expected to reopen today.
Transport Agency acting southern region director Ian Duncan said contractors had cleared three washouts on State Highway 6 near Makarora, and were working on two slips in the Haast Pass area.