Authorities have issued health warnings for Melbourne as bushfire smoke degrades the air quality across the city, as major fires in Victoria could continue to burn for days or even weeks.
Air quality was rated the sixth worst in the world on Sunday morning, according to IQAir, with Vic Emergency saying weather conditions could cause smoke to travel and linger.
Bureau of Meteorology (BoM) forecaster Diana Eadie said the smoke would linger for certain communities, but it had largely cleared in Melbourne by mid-afternoon.
Heatwave warnings are in place for every mainland state and territory, with some capital cities surpassing 40C this long weekend, as firefighters continue to battle bushfires in Victoria.
And a cyclone is threatening homes and infrastructure on the other side of the country, with communities in Northern WA bracing for flooding.
Heatwave warnings
While there are more severe heatwave warnings in place than extreme warnings, authorities say everyone in these areas could be at risk of the heat.
Adelaide has a forecast top of 45C on Monday, Melbourne is tipped to hit a high of 43C on Tuesday and Canberra is bracing for 42C on Wednesday.
BoM has forecast potentially catastrophic bushfire danger as an intense and long-lasting heatwave drags across NSW, South Australia, Victoria and southern Queensland.
These states, along with the ACT and Northern Australia, are experiencing low to severe heatwave warnings, with a maximum danger in place across the desert where the WA and SA borders meet.
In NSW, an extreme heatwave warning is in place for the Snowy Mountains and South West Slopes, with the BoM saying that heatwave conditions across the state are "expected to intensify this weekend and early next week".
Parts of North East Victoria are also at the extreme warning level, where the BoM is forecasting that maximum temperatures could reach the mid-40s.
In South Australia, there is an extreme heatwave warning for Flinders.
The rest of mainland Australia is experiencing a less intense heatwave warning level, while Tasmania is the only jurisdiction without a heatwave risk as of Sunday morning.
The BoM recommends seeking a cool location, whether that’s at home, a community centre or a library, to escape the heat and reduce your risk of dehydration and heat exposure.
Victorian fires
Hot to very hot temperatures in Victoria, combined with "dynamic conditions", could lead to major fires burning for weeks to come, according to a Victorian State Control Centre spokesperson on Sunday morning.
They confirmed that a fire in Longwood has now grown to around 133,000 hectares in size, and a second in Walwa is about 121,000 hectares in size.
Over 900 firefighters and almost 200 fire vehicles have been at the scene of those two fires this long weekend.
The spokesperson told SBS News that people should reconsider their need to be outdoors in proximity to the fires, and follow the total fire bans in place.
"Disappointingly yesterday, during a statewide total fire ban, more than 20 fires that started were from campfires, bonfires and burn-offs," they said.
"It is extremely important that people do not light any fires during a Total Fire Ban."
They also urged the public to obey roadblocks and follow directions and authorities.
Several locations in Victoria's north are facing the prospect of seven consecutive days of maximums above 40C.
"We haven't seen heatwave conditions like this in Victoria for almost 20 years," Emergency Management Victoria commissioner Tim Wiebusch said.
Flooding risk in WA
Residents of Western Australia’s north coast faced damaging wind gusts and heavy rainfall from Tropical Cyclone Luana this weekend.
The system, expected to be downgraded to a tropical low on Sunday morning, is packing winds gusts of up to 95km/h and heavy rain across the northwest Kimberley district, BoM said
The area between Broome and Cockatoo Island, including Derby, was expected to bear the brunt of the cyclone as it tracked southeast.
"Tides will be higher than normal between Beagle Bay and Kuri Bay and large waves may produce minor flooding of low-lying coastal areas," the bureau said.
"Wind and rain impacts are continuing near the system centre, predominantly on the southern side of the system."
A cyclone watch and act alert was previously issued for an area from Coulomb Point Nature Reserve to Cape Leveque, both on the Dampier Peninsula, with residents and visitors told to shelter indoors.
BoM forecaster Jonathan How said heavy rain leading to flash flooding was possible.
"This may cause roads to become flooded and communities to be isolated."
— Additional reporting by the Australian Associated Press.
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