The Pukaki Downs blaze has been "unprecedented" due to its behaviour, Fire and Emergency incident controller Stephen Butler says.
Butler held a media briefing this afternoon as crews were fighting another fire nearby at Tekapo, also in the Mackenzie District.
Stephen Butler Photo: RNZ / Nathan McKinnon
"I was talking to a couple of colleagues that have been to a lot of rural fires and they can't believe the fire behaviour. The winds are swirling all around - so not predictable whatsoever.
"We've had two wind changes - (one) last night that actually came in our favour - it took the flames and the direction of travel of the fire away from homes ... which was great.
"In saying that, the residents have done a great job of learning from previous fires and they have now given themselves great defendable space around their homes... it's a natural firebreak... we believe that has helped in the fact that we have not lost any properties at this fire."
About 80 firefighters are helping tackle the fire, with 16 fire tankers and four wheel drive and rural appliances. Another 18 people are in the helicopter teams.
Fire and Emergency will escort people out of the Aoraki Mount Cook area tonight if they want to leave but could not due to the fire.
They are being taken out in a convoy of vehicles that are meeting at the Twin Streams Bridge at Glentanner.
State Highway 80 from Pukaki to Mount Cook will remain closed between the State Highway 8 junction and Lavender Farm until further notice.
The blaze died down overnight but crews knew they were in for another wind change on Thursday, Butler said.
"We were expecting a northwesterly and then a southerly. So everything we have put in place we have got to keep our eyes behind us making sure that our crews are safe for whatever happens.
"That's why it's proving a very difficult fire to fight. We hit it really hard this morning because the conditions were in our favour but unfortunately now... the (eight helicopters) are now grounded because of the high winds."
The Pukaki Downs blaze. Photo: RNZ / Nathan McKinnon
Butler said FENZ had a few days of hard work to come, but teams were in good spirits and there were no injuries so far.
The fire was on Thursday afternoon what FENZ called "contained within our firebreaks during the current weather pattern".
"So if the weather changes again - we're putting things into place because we're expecting it."
So far 165 hectares had burned and the fire had a perimeter of 17 kilometres.
" It's pretty big, yep. It's a big fire," Butler said.
Fire crews were bolstering natural fire breaks and fire breaks they had made.
"The fire moved towards the houses last night, so it burnt the available fuel, then it went away again.
"Like a wave coming into a beach, it's going to come again tonight, but there won't be the same amount of fuel... so we're confident that we're going to be able to keep those properties safe.
"All the properties that were in the line of fire were evacuated last night. They're with family and friends."
Smoke drifting across Lake Pukaki from the large blaze at Pukaki Downs. Photo: RNZ / Nathan McKinnon
Cooler temperatures, less wind, and rain is expected from this evening with snow forecast tomorrow.
But Butler said snow could blanket the fire, making it look like it was out when it was still smouldering underneath.
The cause of the blaze was unknown.
With State Highway 80 closed, Butler said: "Unfortunately, we've probably upset a lot of travellers. People will be trying to get to Mount Cook and I know there are people trying to get out of Mount Cook.
"First opportunity we get, we will come up with a plan to get them able to carry on with their holidays."
MacKenzie District Mayor Anne Munro said the fire had struck on the Thursday before a long weekend, with Monday being South Canterbury Anniversary Day.
She asked visitors to check the weather and road conditions, because severe weather is expected over the weekend.
"Please, if you're coming into the area, just be very mindful of the situation that the district is in, it's under a bit of pressure this weekend," Munro said.
Second large blaze nearby
Fire fighters are also battling another large fire at Mt Gerald station at Lake Tekapo. This fire is not posing a risk to property at present.
Fire crews in the Mackenzie District on Thursday. Photo: RNZ / Nathan McKinnon
Meanwhile, fire crews are responding to a second scrub fire in the Mackenzie district this afternoon at Mt Gerald station. This fire is not posing a risk to property at present.
Fire and Emergency was reported to the fire at Tekapo shortly before 1pm. Seven fire trucks from Lake Tekapo, Ashburton and Fairlie are responding to the fire at Tekapo.
With a strong El Nino predicted this summer, it is likely to be hot and dry - raising the risk of fires.
Butler said people needed to take extra caution with fires this summer to avoid more wildfires.
Speaking to media from Twizel was "starting to become a bit of a habit unfortunately", he said.