Rain isn't always helpful fighting bushfires, so what will it take to put them out?
ABCThe heavens have reluctantly opened, bringing a few millimetres of rain to the scorched south-east, but authorities say it can actually hinder their efforts to fight bushfires. Key points: A cool change has brought temporary relief for the fire-ravaged south-east, but rain can hamper firefighting efforts Rain can prevent back-burning, making it harder to build control lines and lead to patchy burnt areas that can flare up again For rain to extinguish the fires, it will require inches of steady falls over an extended period Up to 15 millimetres was recorded over 24 hours across some parts of the fire zone. "Having unburnt areas within your control lines is actually quite dangerous because they can be a source of new fires or spotfires when things dry out again," Dr Duff said. Dr Duff said the fires could stop if: there was sufficient rain over a prolonged period to wet the fuels — this is potentially sooner around the Queensland border but could be months away in Victoria there was a long period without strong winds that allowed firefighters to contain the fires they ran out of forest to burn What you really want is lots of steady rain, that isn't too hard, over an expended period. Dr Duff said it was hard to say how much rain would be enough to stop the fires, particularly as the current rainfall deficit was unprecedented.