Months of wet weather across eastern Australia may have a silver lining, with the national council for fire and emergency services advising a normal to below-average likelihood of bushfires this spring in regions devastated during the black summer.
The Australasian Fire and Emergency Service Authorities Council released its seasonal bushfire outlook on Wednesday.
Areas across Victoria, New South Wales and the ACT showed below normal fire potential as a result of recent and persisting rain, in addition to low fuel loads in regions still recovering from the 2019-20 bushfires.
“While we’ve got areas that are above normal and below normal, most of Australia during the spring outlook is what we refer to as normal fire potential,” said Dr Simon Heemstra, director of national projects and innovation at AFAC.
“We could still have destructive and deadly fires in those areas, and people need to be vigilant and aware as the season develops if we have some very hot, dry, windy days.”
Fire risk was elevated in some regions where there had been increased vegetation fuel loads after abundant rainfall, AFAC said.
Parts of central Australia and northern Western Australia are predicted to have above normal fire potential due to above-average vegetation fuel loads.
After significant rainfall, “a lot of those mainly grassy and arid areas have received quite a lot of growth”, Heemstra said.
“When the rain stops, that grass will start to die and dry out,” he said, a process known as curing. AFAC forecasted the fuel loads in these regions were “either fully cured or expected to cure with predicted warmer and drier seasonal conditions”.
Factors affecting seasonal fire conditions include recent rainfall, temperature and soil moisture, which affect the amount and type of vegetation fuel available and how dry it is.
Forest fire activity in south-east Australia has historically been lower during years in which there are La Niña or negative Indian Ocean dipole weather events.
Australia is currently experiencing the second of two consecutive negative Indian Ocean dipole events, and the Bureau of Meteorology said last week there was a 70% chance of a third consecutive La Niña returning in spring. Above-average rainfall across much of Australia over winter is expected to persist into spring.
AFAC noted that “some areas in eastern Queensland have received record rainfall totals that were unusual for the northern dry season. During the same period, central Australia received close to average rainfall while much of southern Australia and the far Top End of the Northern Territory saw below-average rainfall”.
“January to July rainfall saw below-average rainfall in northern parts of the NT, southern WA, western Tasmania and southeast SA into western Victoria.”
AFAC’s seasonal bushfire outlook incorporates modelling from the new Australian fire danger rating system, which will launch on 1 September. The system replaces a model that was largely based on science more than six decades old, and calculates fire danger risk with more geographical precision.
“It’s a significant improvement to the science of how we calculate fire danger ratings in Australia,” Heemstra said, adding that the new model took into account eight different fuel types where the previous model only looked at grass and forest.
The rating system includes nationally consistent signs that communicate danger in four levels instead of six: moderate, high, extreme and catastrophic.
