Some of the fires generated so much smoke that they could be seen from satellite cameras above Australia.
According to Weatherzone, there were more than 100,000 cloud-to-ground lightning stikes in Victoria between Sunday and Tuesday.
Bushfires were continuing to burn today in the Grampians National Park.
At 7am today, the fire on the north-west side of the National Park was out of control, with a watch and act warning in place.
A bushfire on the eastern side was said to be under control.
Another bushfire is burning in the Little Desert National Park, further northwest in Victoria.
In South Australia, a bushfire warning was at advice level for a fire in the Mount Remarkable National Park in the Flinders Ranges.
In Tasmania, several fires were burning in the western side of the state.
“There is an uncontrollable bushfire at Canning Peak,” Tasmania Fire Service said.
ADF to build temporary bridge to give access to flood-ravaged town
The fire is moving towards the famous Overland Track hiking trail.
Unusually hot and dry conditions for this time of year are exacerbating the fire risk in South Australia, Victoria and Tasmania.