Brenton Davis, who shot video of one of the tornadoes, said in a Facebook post that it had formed on the north coast of Kangaroo Island, which sits off the coast of south-central Australia.
"We had a fair few [fire tornadoes] today and it wasn't even a hot day," Davis said.
More than 200 fires were burning across the country, officials said Friday, and warnings of extreme danger to come prompted mass evacuations. Traffic was gridlocked as people fled and firefighters escorted convoys of evacuees as fires threatened to close roads. Navy ships were called in to pluck hundreds of people stranded on beaches.
Victoria Premier Daniel Andrews declared a disaster across much of the eastern part of the state, allowing the government to order evacuations in an area with as many as 140,000 permanent residents and tens of thousands more vacationers.
The early and devastating start to Australia's summer wildfires has already burned about 5 million hectares of land, left at least 19 people dead, and destroyed more than 1,400 homes. That's more acres burned in Australia than any one year in the U.S. since Harry Truman was president.
In South Australia state, fire officials said the weather conditions were cause for concern because fires were still burning or smoldering.
This week, at least 445 homes were destroyed on the New South Wales southern coast and dozens were burned in Victoria. Ten deaths have been confirmed in the two states this week, and Victoria authorities also said 28 people are missing. Fires are also burning in Western Australia, South Australia and Tasmania.
The Associated Press contributed to this report.