Professor watches from NT as SA farm burns

A leading academic has watched from Darwin as his farm in South Australia went up in flames in the devastating bushfire north of Adelaide.

The vice chancellor of Charles Darwin University in the Northern Territory, Professor Simon Maddocks, said he watched his farm "explode in a fireball" on Wednesday, one of a number of properties destroyed in the blaze.

"Cameras let me see but helpless to act," Prof Maddocks tweeted.

He was among many people who took to social media to post pictures and provide other information on the fire which was sparked near Pinery around noon and burnt through 85,000 hectares of mainly farmland by Wednesday night, threatening several towns.

Others showed images of sheds and buildings on fire, burning cars that had been abandoned and homes that were destroyed or damaged.

Two people were confirmed dead in the fire and fears were held for a third in what Premier Jay Weatherill said was "the worst of news".