A CFA Member works on controlled back burns along Putty Road on November 14, 2019 in Sydney, Australia.

Australia's most populous state was paralyzed by "catastrophic" fire conditions Saturday amid souring temperatures, while one person died as wildfires also ravaged the country's southeast.

"Catastrophic fire conditions are as bad as it gets," New South Wales Rural Fire Services Commissioner Shane Fitzsimmons told reporters. "Given we have a landscape with so much active fire burning, you have a recipe for very serious concern and a very dangerous day."

Areas in western Sydney were forecast to hit 47 degrees Celsius (115 Fahrenheit). A cooling change was expected to move through New South Wales late Saturday although authorities warned that strong winds could push fires in dangerous new directions.

New South Wales is in a seven-day state of emergency as around 2,000 firefighters battle 100 wildfires.

Two firefighters died Thursday battling blazes southwest of Sydney. Geoffrey Keaton, 32, and Andrew O'Dwyer, 36, were in a truck convoy southwest of Sydney when a tree fell and caused the vehicle to roll off the road.

Authorities confirmed Saturday one person died and 15 homes were destroyed in South Australia as a wildfire ravaged the Adelaide Hills on Friday, just 40 kilometers (25 miles) from the state capital of Adelaide. Another person was critically injured after fighting to save his home from the fires.

It follows the death of a 24-year-old man in a road crash in South Australia on Friday, which sparked a fire in the area of the Murraylands.

Authorities said 23 firefighters and several police have also suffered injuries, as more than 40,000 hectares (98,842 acres) burnt across South Australia.

"It is going to be a real scene of devastation, especially for those people in the Adelaide Hills who have been most affected," South Australia Premier Steven Marshall said.

"We know that in addition to the buildings and vehicles lost there are very significant losses in terms of livestock, animals, crops, vineyards."