The Bureau of Meteorology says damaging fires and deadly heatwaves could strike early this year as weather systems combine to create tinderbox conditions.

A positive Indian Ocean Dipole (IOD) has strengthened significantly, with the latest recorded values the strongest since 2001.

Characterised by cooler waters to the northwest of Australia and warmer waters further west, a positive IOD usually brings below average winter and spring rainfall to southern and central Australia, and warmer days.

“Positive IOD events are often associated with a more severe fire season for southeast Australia,” the Bureau says.

In addition, Australia is facing a prolonged period of negative Southern Annular Mode (SAM). Largely due to a sudden warming of the stratosphere over Antarctica, a negative SAM brings drier than average conditions to eastern Australia.

The Bureau’s latest outlook for October to December warns that the dry and warm start to spring is likely to continue to the end of the year

“The month of October has a high chance of being drier than average for virtually the entire country, while October to December sees drier than average conditions very likely for most of southern and eastern Australia,” Senior Climatologist Andrew Watkins said.

“Days are very likely to remain warmer than average across Australia. This also means there is an increased chance of early heatwaves, and windy days will see very high fire danger.”

The Bureau has activated its heatwave service, which uses maps to show heatwave location and severity.

Heatwaves, which kill more Australians than any other natural disaster, are defined as three or more days in a row when both daytime and night-time temperatures are “unusually high”.

“We’ve already seen above average temperatures and fire weather conditions across parts of Australia so far this year,” Bureau public safety GM Shoni Maguire said.

“Early preparation is critical, so it is important the community keeps up-to-date with the latest weather conditions.”