Bushfire area a factor in spot fires developing a long way from the fire front

Spot fires can be a major driving force behind bushfire spread and now Australian research has found that the area of a source bushfire is the strongest predictor of whether long distance spot fires will develop away from the fire front. Spot fires can ignite many kilometres downwind from a fire front, driving bushfire spread, particularly in ‘extreme’ wildfires such as those experienced this summer. The researchers analysed more than 300 spotting wildfires in south-east Australia between 2002 and 2018 and found the area of the source fire was the most important predictor of maximum spotting distance and the number of long distance spot fires produced. Weather factors such as wind speed, vegetation and the physical features of an area also had secondary effects.