Extreme heat and dry weather are forecast to fuel more bushfires in summer, with El Niño expected to hit Australia by the end of the year.

The Bureau of Meteorology has declared a 70 per cent chance of the weather phenomenon, which reduces rainfall, increases daytime temperatures and bushfire danger.

CSIRO senior research scientist Dr Nandini Ramesh said it is difficult to predict the strength of El Niño’s impacts.

“Some of the worst bushfire seasons in Australia have been during weak to moderate El Niño events, rather than strong ones,” Dr Ramesh said.

El Niño is a complex weather event where the tropical Pacific Ocean temperature becomes warmer.

This causes warmer trade winds from the Pacific to swing further east, making weather conditions hotter and drier in Australia.

During a La Niña event the opposite occurs and cooler water from the Pacific Ocean is brought to Australia’s eastern coast.

The effects of warmer weather are already being felt in eastern Australia where ski resorts were closed at the start of the ski season due to lack of snowfall.

Last year, Thredbo ski resort opened up with a massive 125cm of snowfall early in the winter, but this year the NSW alpines are yet to see any snow.

The strong La Niña event from 2020-22 promoted cooler conditions for most of Australia and is likely to be linked to abundant snowfall seen in NSW last year.

University of NSW climate change research adjunct fellow Dr Tom Mortlock said that scientists are now more confident in El Niño forecasts than they have been in the past.

“The concern now is that – with the long absence of El Niño and back to back La Niñas – the landscape is preconditioned for bushfire with significant fuel growth occurring,” Dr Mortlock said.

BOM senior climatologist Catherine Ganter said that the impact of El Niño varies from event to event and also depends on location.

“The Bureau’s long-range winter forecast is for drier and warmer conditions across almost all of Australia,” Ms Ganter said.