Photo: A large convective column of air over the fire at Mount Buffalo could start spot fires. (ABC News: Ashlee Aldridge)
A fire at Mount Buffalo in Victoria's Alpine Region is expected to flare this afternoon, creating spot fires which could threaten communities as a strong and erratic southerly wind moves through the area.
Authorities have urged people at Buffalo Creek, Buffalo River, Merriang, Merriang South, and Nug Nug to head north to avoid the fire, which has been burning around the north-western side of Mount Buffalo for days.
An evacuation warning for those communities said if the fire began to produce its own convection column this afternoon, there would be "high potential" for spotting into the Buffalo Valley.
A relief centre is open at the Myrtleford Senior Citizens Centre on Smith Street, while the Latchford Barracks in Bonegilla is full and no longer accepting people.
Incident controller Michael Masters told ABC Goulburn-Murray wind speeds of up to 50kph combined with fire activity would increase the fire's intensity "significantly".
"For local residents, they would be well aware of what I'm talking about between three and four o'clock yesterday afternoon there was a really large plume development over the top of Mount Buffalo," he said.
Mr Masters said intense heat would create a convection column, caused by air moving rapidly upwards and sucking fuel up with it, such as leaf litter, bark and small twigs.
"And the risk of that is there's a lot of small pieces of burning material suspended in the atmosphere," he said.
"The convection column can push through the inversion layer and actually lean over or be pushed over by the wind and those pieces of burning material can drop out in front of the fire front and start new fires."
Evacuating area 'the safest option'
Mr Masters said he hoped ordering people to evacuate towards Myrtleford was "an overreaction".
"But given the topography there and the fact that there's only really one road in, and one road out, for those communities, it's the safest option."
He said it was possible wind speeds combined with spot fires could stop people reaching safety, and he was not willing to take that risk.
"And I don't think the community would want to accept that risk either," he said.
"Hence the recommendation to move while we still have time to an area that's safe.
"Go and do a bit of shopping, go and visit the pool or go and watch a movie in Wangaratta. But at least you'll be safe."
Mount Buffalo Chalet being protected
Despite fears circulating online, Mr Masters confirmed the Mount Buffalo Chalet had not been damaged.
Asset protection was undertaken to ensure the chalet and other infrastructure such as Telstra towers were safe, he said.
"We've removed all the fine fuels from around those buildings and outbuildings and prepared them as best we can an eventuation of fire occurring near them."
Other asset protection strategies include turning on sprinkler systems, filling water tanks and a 300,000 litre swimming pool, and deploying lines of fire retardant around the Chalet and other assets.
Historical items of significance were also removed and placed in secure storage.
Mr Masters said firefighters understood the historical significance of the Chalet "and its deep connection within the broader community".
"That said, the preservation of the life, of both residents and firefighters, remains our highest priority and will not be compromised," he said.
The fire has a perimeter of approximately 550 kilometres and is being managed from the Ovens Incident Control Centre.