I'm curious at the use of acres in this article, or even otherwise. This is about 6070 km square kilometers, which is a square of about 77 kilometer.
https://graphics.reuters.com/AUSTRALIA-BUSHFIRES-SCALE/0100B...
I suspect that acres were chosen because it is a reasonably familiar unit, given the organ is NPR, and makes for a huge number. If you are aware of an acre, you will know it is a fair sized bit of land and 1.5M of them is absolutely huge.
For us European types (lol - UK) 0.3 Wales or 0.2 Belgiums gives an idea as to absolutely awful these fires are.