A toxic haze blanketed Sydney Tuesday triggering a chorus of smoke alarms across the city as severe weather conditions fuelled deadly bush blazes.
Fire engines raced office to office in the city center with sirens blaring as inland bushfires spewed smoke laden with toxic particles into commercial buildings.
Emergency services responded to an "unprecedented" 500 automatic call-outs in just a few hours, according to New South Wales Fire and Rescue's Roger Mentha.
A thick blanket of smoke in Sydney triggered dozens of false fire alarms, Australian authorities said.
A regional fire headquarters miles from the nearest blazes was itself evacuated, while throngs of mask-wearing commuters choked their way through thick acrid air and the organizers of a harbor yacht race declared it was unsafe to proceed.
"The smoke from all the fires is just so severe here on the harbor that you just can't see anything, so it's just too dangerous," said spokeswoman Di Pearson of an event that normally foreshadows the famed Sydney-Hobart yacht race. "The vision is just so poor."
Some of the city's commuter ferries were also canceled "due to thick smoke," and school kids were kept inside at breaktime and sent home early as pollution levels soared far above "hazardous" levels.
For weeks the east of the country has been smothered in smoke as drought and climate-fuelled bushfires have burned, but the scale of the problem on Tuesday shocked even hardened residents.
Bruce Baker – an 82-year-old who lives in Gosford, north of Sydney – said he was skipping his daily morning walk because of the smoke.
"This is the worst it's been, for sure," he told Agence France-Presse (AFP). "It dries your throat. Even if you're not asthmatic, you feel it."
Authorities recommended that the vulnerable cease outdoor activity altogether and that everyone stay inside as much as possible.
Tuesday had been expected to bring strong winds and high temperatures that made for "severe conditions where embers can be blown ahead of the fire into suburbs and threaten properties."
But New South Wales Rural Fire Service said "deteriorating fire conditions have been delayed by a thick blanket of smoke" over the east of the state.
"Strengthening winds may see fire conditions worsen this afternoon," the service said.
As the day developed there were nearly 100 bushfire incidents in the state of New South Wales alone and dozens more in Queensland.
Total fire bans were put in place across much of the east of the country and in large parts of Western Australia.
Temperatures in some inland areas eased past 44 degrees Celsius.
The 'big dry'
To the northwest of Sydney, several fires already burning for weeks have combined to create a "mega fire" that has already destroyed 319,000 hectares of land, mostly inside national parks.
Prime Minister Scott Morrison, who for weeks has not commented on the smoke haze, defended his government's handling of the fires and said there were no plans to professionalize the countryside's largely volunteer force.
"Our policy is sensible when it comes to addressing and taking action on climate change. Our actions on climate change are getting the results they're intended to get," he said.
Morrison's conservative coalition has been criticized by former fire chiefs for failing to heed warnings about climate change.
The crisis has been propelled by a prolonged drought that has made vegetation tinder dry.
The Bureau of Meteorology has reported that Australia experienced its driest November on record this year.
The "big dry" has left farmers desperate and small towns facing the prospect of running out of water completely.
A swathe of the east of the country has seen "rainfall deficiencies" since early 2017.
Many dams in New South Wales are empty, and almost all are well below capacity.
Firefighters south of Brisbane recently reported 1,000 liters of water had been stolen from tanks at their station.
Amid the shortage, Tuesday also saw the toughest water restrictions in a decade being introduced for Sydney, with curbs on everything from hose use to washing cars.