Three years of La Nina drenchings have delivered a mostly normal bushfire outlook across Australia this winter but long-range weather forecasts are stirring some early concerns for higher-risk periods further ahead, with Black Summer memories all too recent. 

Plentiful rainfall in the past few years has supported abundant vegetation regrowth, adding to potential fuel loads that can elevate risk levels should favourable bushfire weather conditions shift the dial. 

The Bureau of Meteorology last week forecast a high chance of below average rainfall for large areas of Australia for June to August, along with warmer than usual temperatures, with the outlook following on the heels of a relatively dry autumn. 

Australia’s autumn rainfall was about 10% below the 1961-1990 average and each state and territory had below average rainfall overall, except WA. The nation had its second-driest May since national records began in 1900, with rainfall about 73% below the 1961-1990 average. 

Bureau Extended Prediction Technical Lead Catherine Ganter says there’s a high chance of below average rainfall continuing in winter, particularly in some regions. 

“Southern areas have at least twice the normal chance of winter rainfall falling in the bottom 20% of records,” Ms Ganter said. 

The winter long-range forecast reflects climate influences such as the chance of El Nino forming in the Pacific Ocean, signs a positive Indian Ocean Dipole may emerge and warmer-than-average ocean temperatures around Australia. 

“If a positive Indian Ocean Dipole occurs with an El Nino the drying effect is typically stronger and more widespread across Australia,” Senior Meteorologist Angus Hines says. 

AFAC, the national council for fire and emergency services, sees normal bushfire potential for most of the country over winter, with areas of above-normal risk across a large area of the NT and pockets of NSW and north-western SA. 

The report also flags some positive and negative influences for states and territories leading into the spring and summer bushfire seasons. 

Positives include favourable conditions in southeast Queensland for early winter season mitigation burning, given soil and fuel moisture levels. 

“Many eco-systems are forecast to be favourable for seasonal burning to achieve both an ecological and risk reduction benefit for communities,” AFAC says in the Queensland summary. “Moving into the cooler months, we are not likely to see a notable change in the fuel accumulation through winter, leading into the spring fire season.”  

In parts of the NSW Great Dividing Range, fuel loads remain reduced due to the Black Summer fire season, and despite quicker than normal regrowth, the areas have below normal fire potential for winter. 

The Rural Fire Service will be closely monitoring fuel loads regrowth over the next few months and into the next fire season.  

SA has seen rapid drying out of above average fuel loads, leading to above average Forest Fire Danger Index ratings starting to be seen in the lower western Eyre Peninsula and far southwest of the state.  

From June to August, most of the lower south of the state is predicted to be in the lowest 20% of historical averages of rainfall, combined with most of the state being in the top 20% likelihood of well above average temperatures. 

Mallee heath landscapes are forecast to have a high chance of exceeding the median Fire Danger Index range from June to August and grassland in SA is noted amongst national fire danger risk areas.  

AFAC says Victoria enters winter with wetter soils across the state after the La Nina years, but the forecast drying pattern will be monitored to identify emerging risks and any potential for an earlier start to the bushfire season. 

Good fuel reduction opportunities are also seen in Tasmania, although the below average winter rainfall outlook raises concerns that this could result in an earlier start to the fire season in spring.  

“Abundant fuel growth from successive wet (La Nina) years, coupled with forecast below average rainfall, may result in above normal fire potential in some areas in the spring period,” it says. 

For much of the country overall, the combination of reduced rainfall and above average temperatures and evaporation results in outlooks for drier than average root zone soil moisture by late winter, AFAC says. 

Looking overseas, Australian firefighters have travelled to Canada in recent weeks, as that country battles wildfires in both eastern and western provinces, in a reminder of the increasing global risks. 

NSW said last week that 57 specialists from the state’s firefighting and emergency service agencies had arrived to join a 200-strong Australasian deployment assisting Canadians battling more than 190 blazes through the provinces of Alberta and British Columbia. Canada has also called on assistance from other countries in controlling fires in Nova Scotia. 

Australia is still recovering from the heavy cost of last year’s record flooding, but as conditions change it’s a reminder there’s no room for complacency as the local bushfire risk potential comes back onto the radar all too quickly.