The Mt Allan Forest fire has now consumed 820 hectares of trees and scrub since breaking out about 4pm on Tuesday in a cut-over forestry block just above the Taieri River.
Principal rural fire officer Graeme Still said a wind shift from a northerly earlier today to a westerly had relieved worries the fire might burn under electricity cables, and that during the afternoon the wind speed had dropped to about 20kmh, It was up to 60kmh earlier in the day.
One crew will be left to keep an eye on the fire overnight.
Tomorrow Mr Still plans to mount a big ground-based operation with over 40 firefighters split into eight crews. Some will work with helicopter pilots dropping water scooped with monsoon buckets from the Taieri River, and others will use bulldozers and diggers to open up ground on the fire's most active front so that the water can penetrate to burning roots and other material.
Some of the ground crews were today able to tackle the blaze head on after spending much of the past few days relying on the efforts of 10 helicopters and a fixed wing aircraft.
Firefighters have also been working to ensure Dunedin's Silverstream water catchment area several kilometres away to the east was protected.
The fire's size increased by only about 100 hectares today.
Dunedin City Council civil defence and rural fire manager Neil Brown said a national incident team had arrived today to help with logistics and while the fire was being contained, it was not yet controlled.
The five families evacuated so far will remain away from their homes overnight.
Walking tracks in and around the area remain closed, while trips by the Taieri Gorge excursion train across the southern part of the forest have been cancelled.
These measures will be reviewed tomorrow morning.
Dunedin City Council and neighbouring Clutha and Southland district councils, the Department of Conservation, Civil Defence and police have been involved in fighting the blaze, in addition to the company that owns the forest Wenita Forest Products.
The fire apparently started from a spark caused by friction from a logging rope, Wenita head David Cormack said.
It was too soon for the company to estimate its financial losses as a result of the fire.
Mt Allan Forest comprises a single block about 10km north of Mosgiel, and covers 4958 hectares, of which 4420 hectares is growing trees or awaiting replanting. The forest covers an area of steep and very steep slope ranging from inland hills through to the Otago uplands. Dunedin City Council water pipelines cross the south corner of the forest as do high-tension powerlines.
The forest mainly grows radiata pine but also has some douglas fir and eucalypts.
Earlier report: The weather gods have this morning finally smiled on firefighters battling an enormous blaze in forest land 30km northwest of Dunedin.
Nine helicopters took to the skies this morning to continue their assault on the flames that have razed more than 700 hectares since Tuesday.
Forest owners Wenita Forestry Products said the strong winds that had been fanning the flames had died down overnight.
Ground crews and machinery were now able to move in to tackle the flames.
The wind direction had also changed to the southwest, which had pushed the wind from moving over Dunedin city back to over the forestry area, Mr Kerr said.
The national rural fire management team had flown to the area and would take over operations today.
Ideally firefighters needed the cold conditions to remain for there to be any chance for them to take control of the fire, Mr Kerr said.
Fixed wing planes were also going to use fire retardant over the area today.
By late last night the fire had destroyed more than 700ha of forestry land and it is expected to take days to contain it and weeks or months to subdue hotspots.
At least 10 helicopters spent yesterday attacking the blaze in Wenita Forestry's Mount Allan Forest, about 10km north of Mosgiel and 20km northwest of Dunedin.
A fixed-wing aircraft dumped fire retardant on the flames, where possible, and a ditch-digger worked on creating firebreaks.
Rural firefighters from Wenita and the Dunedin City Council were on stand-by near the fire, because it was still too dangerous for them to fight the fire from the ground.
Council principal rural fire officer Graham Still said by 9pm the fire was still moving, but had slowed considerably.
The fire was in both trees and logged areas.
The past two days had been "bad days", but his main concern now was the westerly winds expected today, which could push the fire into more vegetation.
Glenn Mitchell, from the council's emergency operations centre, said the fire was left to burn last night, to rest crews.
One helicopter remained on site, ready to fly, fitted with night-vision equipment, in case of any flare-ups.
The national incident team, of about four experienced rural firefighters, would arrive this morning to assist with fire management and provide relief cover for Dunedin crews.
Council civil defence and rural fire manager Neil Brown said a "handful" of people from three homes on the eastern side of the fire, and two about 5km south of the fire front, had been evacuated.
The evacuations were precautionary, and were carried out only because staff did not want people trying to move out in the dark.
Planning for the evacuation of other North Taieri homes had also been completed, although it was unlikely it would be required, he said.
Although the fire had slowed down considerably, wind and heat had fanned it and rain forecast for last night was not expected to be as much as was hoped.
The weather conditions were expected to be unfavourable today, as well.
Some roads and walking tracks into the area are closed and the Taieri Gorge Railway will be closed for a second day today.
A group of school children from Tahuna Intermediate was moved as a precaution from one camp site at Tirohanga, to join others on camp at Whare Flat.
Dunedin city and the Taieri Plain were shrouded in smoke for much of yesterday morning, prompting authorities to issue a health warning.
Mr Brown said the fire retardant had stopped the fire entering the council's water catchment area and power transmission lines running to the south of the fire area were not under threat.
The fire, which is believed to have started from a spark from logging machinery on Tuesday afternoon, has so far destroyed about a sixth of the Mount Allan Forest block, which has about 4420ha of land in trees or awaiting replanting.
Mr Brown said he expected the cost of the fire would be more than $1 million, including the cost of the helicopters, at an estimated $20,000 per hour, and the cost of stock losses.
Wenita Forest Products chief executive Dave Cormack said the fire initially burned mostly "cutover" forest logged during the last year.
Wenita had "comprehensive" fire insurance that covered both the damage to the forest and the cost of fighting the fire.
"We're in discussions with our insurer at the moment and we have been in close contact since the fire started.
"They have a good understanding of what's going on."
Mr Cormack said the cause of the fire was not known.
"It could have been any number of things that started it and until we're able to do a full fire investigation once the fire's out we really don't know."
Forestry crews were working in the area at the time and there has been speculation they may have inadvertently caused the fire.
"It is one of several possibilities.
"I'm not denying it's a possibility but there are various other possibilities, as well.
"We've had four weeks of hot, dry windy weather and the forest was particularly dry and, I guess, particularly vulnerable to this type of incident."
Mr Cormack said Wenita monitored "fire-weather conditions" daily but had not got to the point of stopping work during the dry spell of the last few weeks.
"The fire danger does need to be very extreme before we would look at curtailing the forestry operations but [conditions] certainly have been very high in recent times."
Mr Cormack said Wenita was taking a "very cautious" approach to fighting the fire.
"Personal safety is our number one priority and we're making sure that everything is absolutely safe before we put aerial, and especially ground, operations in to fight the fire."
Transpower spent the day closely monitoring four 220kV power lines running to its Three Mile Hill and Halfway Bush substations.
Communications manager Rebecca Wilson said Transpower had a contingency plan to direct electricity from another supply if the circuits needed to be shut down.
An Aurora Energy spokesman reported no action had been required.
Wenita Forest Products Ltd is a private, New Zealand registered and operated company owned by Chinese company Sinotrans (62%) and American investment fund Fund 7 Foreign LLC (38%).
City Forests crews are continuing logging operations but on high alert and with firefighting equipment on hand.
Chief executive Grant Dodson said last night he had been concerned about the potential spread of the Wenita fire into city forests.
However, the nearest block, Ferny Hill, was about 3km from the fire and at last report the fire was heading in the opposite direction.
The big burn
- About 700ha burnt by yesterday afternoon
- Expected to be days before fire contained
- At least 10 helicopters fight blaze
- Five houses evacuated
- Plane drops fire retardant
- Helicopters stood down overnight
- 30 volunteer rural firefighters on stand-by
