A water-bombing plane was missing and feared to have crashed in Australia's southeast on Thursday, as firefighters battled a new outbreak of bushfires whipped up by scorching temperatures and strong winds.
At least seven blazes were declared emergencies, including one in the Snowy Monaro region, where authorities lost contact with the firefighting aircraft.
"Local ground crews indicate the aircraft may have crashed," the New South Wales Rural Fire Service said in a statement.
"A number of helicopters are in the area carrying out a search."
Bushfires also forced the closure of Canberra Airport, with all flights in and out of the country's capital suspended due to approaching flames.
Passenger flights were halted around midday (0100 GMT) as two out-of-control blazes burning immediately to the south and west of the airport merged and the combined fire bore down on three nearby suburbs.
Temperatures soared to 40 degrees Celsius (104 degrees Fahrenheit) in Sydney, where a bushfire also broke out in a northwestern suburb of Australia's biggest city.
Wind gusts had been forecast to reach 90 kilometres per hour (55 miles per hour) in some areas, but New South Wales Rural Fire Service commissioner Shane Fitzsimmons said the winds were stronger than expected, especially in the fire-ravaged southeast of the state.
"One of the big challenges we've got with the increased intensity of these winds is that it is proving very difficult to fly any aircraft to provide any aerial support to the firefighting effort on the ground," he said.
"We are trying to get some of the large air tankers and some of the very large helicopters involved, but it's proving very difficult. It's too dangerous to fly these things."
Fitzsimmons warned of a "long, difficult afternoon" ahead for firefighters and residents.
'A long way to go'
Unprecedented bushfires fuelled by climate change have killed at least 29 people and devastated vast swathes of the country since September.
The blazes have been followed by extreme weather that has hampered clean-up operations in some areas, including intense storms that have battered parts of Australia with giant hail, floods and landslides.
Heavy rainfall has helped to contain and, in some cases, extinguish long-running blazes but an expected return to searing heat and gusting winds Thursday was flagged as a cause for concern as dozens of fires continued to burn.
Cooler weather was forecast to return on Friday, but the bushfire season still has weeks left to run.
"The fire season doesn't traditionally stop here in New South Wales until right up to the end of March," Fitzsimmons said.
"So we've got a long way to go this season and whilst the rainfall has been certainly welcome and the conditions have eased, we're certainly not out of the fire season yet."
The months-long crisis has sparked renewed calls for Australia's conservative government to take immediate action on climate change, with street protests urging Prime Minister Scott Morrison to reduce the country's reliance on coal.
A major coal conference in Wollongong -- situated in a coal-producing region south of Sydney that has been hit by massive blazes -- was cancelled this week in response to what local climate activists said was a "planned mass protest".
And a January poll released this week found the environment has soared to the top of Australians' concerns, with 41 percent of people polled by market research firm Ipsos ranking it as the most important national issue for the first time.
While Morrison has now reluctantly acknowledged the link between the bushfire disaster and a warming planet, he has stopped short of announcing any sweeping new measures to cut emissions.
Instead, the prime minister has signalled that his government would focus on climate adaption and building resilience.