Forget any hopes of drought-breaking rain over summer. The only good news for the large areas of NSW in drought is that there isn’t much left to burn once the fires start.
The bad news is the fires are likely to start earlier, and there will be more of them. Likewise, heatwaves.
There was teasing talk in the past months about a La Niña event bringing relief to a country that overall has experienced a protracted dry, warm period, including a notably hot April that set the tone for winter.
Summer rains? Forget about it
With the vague promise of a La Niña generating heavy rain, of the sort that caused flooding in 2010 and 2011, there was tempered optimism that Australia may have been spared a brutal fire season and that the drought crippling farmers in NSW and Queensland would finally be broken.
But in the past two weeks, the Bureau of Meteorology has revised its ENSO Outlook to “El Niño Alert”, meaning the chances of an El Niño forming during spring is now 70 per cent, or roughly three times, the normal risk.
According to the BoM, the tropical Pacific Ocean and the overlying atmosphere have been warming, indicating the early stages of an El Niño event could already be underway.
El Niño typically results in below-average spring rainfall for northern and eastern Australia, and warmer days for the southern two-thirds of the country.
Bureau of Meteorology manager of long-range forecasting Dr Andrew Watkins said if the El Niño conditions were to occur, the chances of drought-affected areas in eastern Australia making a recovery over the coming months would be lowered.
“Like everyone in the Australian community, the Bureau of Meteorology is hoping regions being affected by drought will recover soon. However, if an El Niño were to occur, we’re more likely to see drier and warmer-than-average conditions,” Dr Watkins said, in a statement on the BOM website.
The hot, dry conditions will be further exacerbated if a positive Indian Ocean Dipole (IOD) event is under way – the Indian Ocean getting warmer – which seems likely.
Aside from these events, the BoM says Australian climate patterns are also being influenced by the long-term increasing trend in global air and ocean temperatures.
Which are on the up. According to the Bushfire and Natural Hazards Co-operative Research Centre, the dry and warm winter has led to poor vegetation growth for most of southern Australia.
“The general landscape dryness means that warm, windy conditions are likely to see elevated fire risk, and make an early start to the fire weather season likely,” the centre notes in its Hazard Note Southern Australia Seasonal Bushfire Outlook 2018.
At least there’s nothing left to burn
Countering this risk, the poor growth of grass and annual plants means that vegetation loads are reduced in drought-affected areas. That is, there is less to burn when the fires start.
Further north, though, low rainfall conditions since March mean that vegetation is dry with very low greenness evident in satellite data, meaning that the northern fire season is well under way.
The centre reports that fire season severity is increasing across southern Australia as measured by annual indices of the Forest Fire Danger Index. The increases are tending to be greatest in inland eastern Australia and coastal Western Australia.
However, above-normal fire potential lies in a thick band that runs from north of the Queensland border, and runs unbroken down the NSW coast and into Gippsland in Victoria.
Parts of the Riverlands, Murraylands and the Flinders Ranges are particularly dry, which means that areas of scrub and woodland have increased fire potential, along with the south-west corner of Western Australia.