An El Nino event could develop as early as July, potentially increasing bushfire risks in summer but reducing the chance of tropical cyclones in Queensland, according to the Bureau of Meteorology (BOM).

The systems are usually associated with below-average rainfall over southern and eastern inland Australia, with about two-thirds of El Nino events since 1900 leading to major droughts. They also bring warmer temperatures.

“The combination of the two gives a higher fire risk going into the spring and summer in eastern Australia,” BOM Climate Prediction Services Supervisor Andrew Watkins told insuranceNEWS.com.au.

The BOM says there is at least a 70% chance of an El Nino developing. Assessments are based on sea temperatures and atmospheric conditions in the tropical Pacific Ocean.

The fire risk increases if an El Nino is combined with a positive Indian Ocean Dipole – where cooler-than-normal tropical east Indian Ocean temperatures reduce the amount of moisture carried on the jet stream across Australia.

“Some of the models we survey are just starting to show the possibility of a positive Indian Ocean Dipole,” Dr Watkins said.

Sea temperatures in the region are currently still warmer than normal.

An El Nino would reduce the risk of cyclones in Queensland because warm waters that fuel the tropical storms would be pushed further away from the east coast.

The US Climate Prediction Centre says there is more than a 65% chance of an El Nino developing during the northern summer.

It says an El Nino leads to more eastern Pacific hurricanes and fewer Atlantic hurricanes.

“The chances for the continental US and the Caribbean Islands to experience a hurricane increase substantially during La Nina and decrease during El Nino,” it says.

Other potential El Nino effects include increased risk of drought in southeast Asia and wet weather in western South America.