Fire has hit a Victorian coastal holiday town and people are being told to go into the water as warning sirens sound.
Thick black smoke billowing from infernos in Victoria and New South Wales states turned the morning sky pitch black or choked the coastline in a haunting red haze.
The annual Australian fire season, which peaks during the Southern Hemisphere summer, started early after an unusually warm and dry winter.
Their voracity and reach prompted New South Wales police to say telecommunications would be lost along a 90-mile stretch of the state's coast between Nowra and Moruya, The Guardian reported.
About 5 million hectares (12.35 million acres) of land have burned nationwide during the wildfire crisis, with 12 people confirmed dead and more than 1,000 homes destroyed.
The popular celebrations are expected to attract around a million spectators and generate 130 million Australian dollars ($91mn) for the state's economy.
Some of those trapped in the town posted images of blood-red, smoke-filled skies on social media.
"This is absolutely one of the worst fire seasons we've seen", Shane Fitzsimmons, commissioner of the NSW Rural Fire Service, told a briefing in Sydney.
"There are a number of people who remain unaccounted for-four people, and of course we have fears for their safety", the Premier said. It's also put worldwide focus on the conservative government's climate change policies, with environmentalists saying Prime Minister Scott Morrison's support of the nation's massive coal-export industry has worsened conditions.
The wildfire crisis has reignited debate about whether Prime Minister Scott Morrison's conservative government has taken enough action on climate change.
People evacuating on boat in Mallacoota, Victoria, Australia are seen is this still image from a December 31, 2019 social media video. Residents returning home were urged to boil tap water before drinking it.
Victoria Emergency Management Commissioner Andrew Crisp said some communities in the state remain isolated, and food packs and other supplies are being organized for transport.
Hunkered down in a building on the town's main street, a community radio presenter, Francesca Winterson, described the situation as "absolutely horrific". The city was granted an exemption to a total fireworks ban in place there and elsewhere to prevent new wildfires. Across Victoria, 70 new fires started on Monday, of which more than 20 are still active.
ABC News in the United States told readers how "thousands" were at risk due to Australian wildfires.
Authorities said it would go ahead, despite some public calls for the fireworks to be cancelled, in solidarity with fire-hit areas in New South Wales. "The other person that we are trying to get to, we think that person was trying to defend their property in the early hours of the morning".
Fire conditions worsened in Victoria and New South Wales after oppressive heat Monday mixed with strong winds and lightning.
A volunteer firefighter in NSW was the latest casualty when a truck he was riding in crashed and rolled over in the high winds.
McPaul became the third NSW firefighter to die in the past two weeks fighting the continued bushfires. He was an expectant father.