Potential remains for severe southern NSW, Victoria bushfires
Potential remains for severe bushfires in southern NSW and Victoria this summer after an early active start to the season, despite recent rainfall, Risk Frontiers says.
Australia experienced its driest-ever September and this month began with multiple fires across NSW and Victoria and a number of houses destroyed in the Bega Valley region. Soil moisture deficits last month were the lowest on record in the bushfire-affected areas.
“Although recent heavy rainfall has temporarily reduced the risk, and the seasonal rainfall outlook is relatively benign, there remains a potential for more severe bushfires in the near future,” Risk Frontiers says in a briefing note.
Australia’s climate this spring and summer is being influenced by an El Nino in the Pacific and a positive Indian Ocean Dipole. The events are typically associated with warmer and drier conditions in southern Australia.
Increased vegetation and fuel loads following three years of La Nina conditions have contributed to concerns, although Risk Frontiers says the primary drivers of catastrophic bushfires are hot, dry winds blowing over a dry landscape.
“Although El Nino has been declared by the bureau and is forecast to continue until at least Autumn 2024, the seasonal rainfall outlook is pointing to average or above average rainfall for most of NSW, providing some hope that the bushfire season might not be that bad after all,” Risk Frontiers says.
Peak bushfire season at any given location generally corresponds to the driest time of year, which is late winter for northern Australia; spring for the Sydney region and mid-summer for southeast NSW and Victoria, the briefing note says.
In NSW 72% of damaging fire events are in summer, 23.7% in spring and 3.2% in autumn, while in Victoria 86.9% are in summer, 8.8% in autumn and 3.6% in spring, PerilAUS data from 1900 to 2022 shows.