"Hopefully some of this heavy rainfall will fall over fire sites and help control or even extinguish fires," Bureau of Meteorology meteorologist Sarah Scully said Wednesday. "But it's a bit of a double-edged sword because heavy rainfall and gusty thunderstorms bring the potential for flash flooding, particularly in the burnt-out areas of NSW and Victoria which are now vulnerable to landslips and trees coming down."
Forecasters said thunderstorms may bring between one and three inches of rain to eastern Australia, not enough to end the drought but at least douse some of the flames from blazes still burning.
Heavier amounts may also fall in areas southwest of Sydney, Australia's 7News reported.
There are concerns the rain will wash harmful ash into waterways that feed into the reservoirs, potentially contaminating the drinking water for millions.
NSW said it is preparing to limit potential impacts on the water quality by placing silt curtains and booms to prevent ash and other debris from getting into Sydney's water system.
Even as officials have said the rain this week won't be intense enough to wash enough debris into waterways, experts have pointed to the scope of burn areas as to why contamination needs to be a concern in the months going forward.
“There are tons of ash in that catchment now,” Stuart Khan, a professor at the University of New South Wales who specializes in water quality and treatment, told The Wall Street Journal. “We can’t expect that we can contain all of it.”
The fires, fueled by drought and the country’s hottest and driest year on record, have been raging since September, months earlier than is typical for Australia’s annual wildfire season. So far, the blazes have killed 28 people, destroyed 2,000 homes and scorched an area of over 25.5 million acres, roughly the size of South Korea.
Recent weather patterns have caused smoke to shroud Melbourne, impacting the Australian Open at Melbourne Park on Wednesday, as smoke and hazy conditions at Melbourne caused the start of play to be delayed by two hours.
Organizers were criticized for allowing qualifying matches to proceed as players dealt with smoke and hazy conditions.
A number of players complained, including Bernard Tomic, who sought medical treatment during his first-round loss when he struggled to breathe. Dalila Jakupovic feared she would pass out before retiring from her match when she collapsed to her knees with a coughing spell, according to The Associated Press.
Canadian qualifier Brayden Schnur was particularly critical of officials after his first-round win over Sebastian Ofner, which took more than two hours in the hazy conditions that blanketed Melbourne Park on Wednesday.
"You feel super dryness in your throat," he said. "That's 100 percent not normal and players who have asthma are at a huge disadvantage right now."
Schnur, who described as like smoking a cigarette, said that top players such as Roger Federer and Rafael Nadal should step up and protest against playing in such poor conditions.
Organizers delayed play on Wednesday but the air quality index when the players took to court was still graded as "unhealthy" because of the smoke from the bush fires in Victoria. The Australian Open begins Monday.
The Associated Press contributed to this report.