farmdoc's blog post number 323

Last 15 February, federal parliamentarian Fran Bailey whose McEwan electorate encompasses much of Victoria’s bushfire region, said schools need to be bushfire-proofed. The next day I wrote ‘…it’s nonsense to suggest that buildings can be designed to be bushfire proof. Resistant to ordinary bushfires, maybe, but not to those as ferocious as last week’s’. In his informative article in the March Monthly, John van Tiggelen agrees: The Forest Fire Danger Index, used since the 1960s, is a composite measure of humidity, wind speed, temperature and fuel combustibility at a given time and place. It’s calibrated so a 100 score reflects the conditions on Black Friday 1939 when fires burnt 5% of Victoria and killed 71 people. Planned burnoffs require a FFDI of under 12; Total Fire Bans are triggered by FFDIs of 50. van Tiggelen writes that days with FFDIs over 100 earn a name: Victoria’s original Black Saturday was in 1977. On Black Saturday II, last 7 February, the FFDI in Kilmore reached 189. He concludes: ‘Black Saturday II is the new Extreme. The old Extreme, the 50-point trigger for a Total Fire Ban, was never more than a starting point – a Category One fire-danger day, say. At this level of risk, there’s little debate: as long as your fire plan’s up to scratch, you have the option of staying to implement it. Where the stay-or-leave-early policy starts to look decidedly shaky is at an FFDI of around 75 points, a putative Category Three. At 100 points, the policy is murder. The next category Five day there’s smoke – and there will be another, probably within the next eight summers – get the hell out’. Are you listening, Ms Bailey?