El Niño to bring extreme heat and fire risk, BoM says

The news: The Bureau of Meteorology has formally declared an El Niño event in the Pacific Ocean, to Australia's east, and a positive Indian Ocean Dipole (IOD), to the country's west. That's triggered warnings of extreme fire risk and heat ahead.

The numbers: Large parts of NSW and eastern Victoria are enduring maximum temperatures 10 to 15 degrees above the September average. El Niño events typically deliver drier conditions for much of the country, but particularly eastern Australia, as well as above-average temperatures.

The context: The declaration coincides with severe weather warnings for swathes of Australia's south east, including very hot spring conditions, elevated fire dangers and strong winds fuelled by an approaching cold front. A heatwave warning is in place for the NSW south coast, and a catastrophic fire danger warning is also current for the state's far south coast. The bureau has been slower to formally an El Niño compared to its international counterparts. A positive IOD often results in less rainfall than average over parts of Australia. When the two patterns coincide it can magnify the drying effects.

What they said: "Both these climate drivers have a significant influence on the Australian climate, in particular favouring warmer and drier conditions, particularly over spring, but also into early summer," BoM Manager of Climate Services Karl Braganza said.