NSW firefighters fought exhaustion and relentless flames as a major weather change created a fresh mega-fire and unpredictable conditions.
Driven by southerly winds gusting up from Victoria, the Green Valley fire, which had ravaged a quarter-million hectares by early Saturday morning, merged with the nearby East Ournie Creek blaze and the huge 312,000-hectare Dunns Road fire to form the state's second "mega-blaze.
As the hills ran red at midnight, the Alpine communities of Mundaroo, Tumbarumba and Mannus were directly in the fire's path.
NSW Rural Fire Service spokesman Anthony Bradstreet said the fires were burning very quickly and could impact rural properties in the area as winds reached 90km/h.
"We are seeing embers burning ahead of the fire front and we could see properties threatened before that main fire front arrives," he said.
Another six blazes – including the massive Border fire – were at watch-and-act level on Friday evening, with most in the state's scorched southeast.
Meanwhile, NSW RFS Commissioner Shane Fitzsimmons said two new blazes – the Yearinan Station Road fire near Coonabarabran in the state's north and another in a remote region of the Blue Mountains – appeared to have begun due to lightning strikes.
Fears rose as the night wore on for the safety of Blue Mountains towns Leura and Wentworth Falls, where 10,000 residents were in the fire's path.
The Erskine Creek fire was burning out of control to the south of Wentworth Falls with a forecast southerly change expected to push the fire towards Leura and Wentworth Falls.
At 3:00am, there were five watch and act alerts in NSW, including Erskine Creek and the Morton fire in the Southern Highlands area near Bundanoon.
Firefighters were set for "a long night," Blue Mountains Mayor Mark Greenhill said in a Facebook post.
"I am sorry the news is not better but tonight is a night of vigilance for us all."
A firefighter in his 20s has been hospitalised and is in a stable condition after suffering burns to his face in the Snowy Valley region when fierce winds pushed the fires in fresh directions.
At Thredbo, snowmaking machines have been running non-stop for days to wet village grounds in a last defence against spot fires ignited by embers riding the gusts coming from the Pilot Lookout fire south of the ski resort.
To the south, over border in Victoria, High Country blazes were threatening the near-deserted towns of Harrietville and Bright.
Victorian firefighters were also facing strong, gusty and unpredictable winds as the weather change moved through
By early Saturday morning an emergency warning remained in place for communities near Mount Hotham in the Alpine region.
Several other emergency warnings in place overnight, including for a grassfire on Wodonga's south-eastern outskirts, were later downgraded.
The danger appeared to be easing somewhat in East Gippsland's Buchan and Combienbar areas, with an emergency warning downgraded by nightfall.
Emergency services hoped rain moving across East Gippsland would help ease conditions.
Incident controller Brett Mitchell in Bairnsdale, however, said there had been significant fire activity around Swifts Creek, Ensay, Omeo and Brookville.
Deputy Incident Controller Jarrod Hayse "Our concern is that the fire in a number of places incl Buffalo Valley, possibly in the Buckland Valley and around the communities of Harrietville, Bright & Myrtleford may seen an increase in fire behaviour" @abcmelbourne @ABCemergency— Ashlee Aldridge (@Ashlee_Aldridge) January 10, 2020
The island's biggest population centre, Parndana, was also untouched despite two fires bearing down on it at the same time.
The towns' reprieve was not without cost.
Two Country Fire Service trucks were involved in burn-overs and two more CFS personnel were injured, taking the island's total casualties to 22 injured and two dead.
With rain falling across the fire ground on Friday, the warning levels for all fires were reduced, initially to a watch and act and then to a simple bushfire advice.
CFS chief officer Mark Jones said Thursday night had been an "incredibly difficult" period for all 280 firefighters on the island.
"Winds were not consistent, they were blustery and came from many different directions," he said.
Mr Jones cautioned that the fires would not be completely extinguished in the short term.
"The changing conditions should allow crews to be successful in reducing spread today and controlling the fires," he said.
"They will not be extinguished today, I would not want anyone to take false hope from that. This is an ongoing and lengthy operation."