A major weather pattern shift is coming to some of the bush-fire zones of Australia, where a relentless, multiyear drought and record-shattering heat turned the landscape into a tinderbox this spring and summer.
The rains are not expected to extinguish all the flames, nor will they end the drought, but they are sure to bring relief for the thousands of firefighters seeking to contain the blazes, which still number more than 100 in New South Wales alone.
The rainfall, though, will also unleash new hazards, since the newly burned regions will be prone to flooding and landslides that could further damage forest ecosystems. This could be worsened by the slow-moving nature of some of the heaviest showers and thunderstorms, according to Sarah Scully, a meteorologist at Australia’s Bureau of Meteorology (BOM).
Given the episodic nature of the showers and thunderstorms, rainfall will be variable, fueled by a frontal zone setting up across eastern Australia that is drawing in moist, humid air from the ocean to the southeast. The BOM is predicting between 1.2 and 3 inches during the next several days across a large area, stretching from Victoria northward into New South Wales and Queensland.
However, some areas could see considerably more rain than this, leading to weather whiplash — literally from hell to high water.
Other regions could see lighter rains, including southern Victoria and South Australia, where bush-fire danger remains high.
Computer models show the heaviest rain may fall in thunderstorms close to the coast, which could keep the highest totals away from areas where large fires are still burning. However, some relief appears likely across a large area. The rains will be heaviest on Wednesday in Victoria and New South Wales and will then spread further northward through late week, Scully said in an online video.
“Hopefully some of this heavy rainfall will fall over the fire sites and help control or even extinguish some of those fires. But it’s a bit of a double-edged sword, as heavy rainfall and gusty winds bring the potential for flash flooding, particularly in the burnt-out areas of New South Wales and Victoria,” Scully said.
She added that these areas are vulnerable to landslides and trees coming down due to sudden downpours. According to the Sydney Morning Herald, officials are working to protect Sydney’s water supply against any mud or ash flows that could overwhelm reservoirs and other water systems.
However, the coming rainfall will not be enough to end the drought, bring an end to the fire season or even extinguish more than a few of the blazes, given the massive extent of many of the ongoing fires. One “megafire,” for example, has measured at least 1.5 million acres alone.
The scale and scope of the bush fires is staggering. In New South Wales, the fires have destroyed more than 2,000 homes. Smoke from the fires, lofted to the stratosphere by towering, fire-induced thunderstorms, is circumnavigating the globe, and the firestorms have wiped out unique natural ecosystems, including species already on the brink of extinction, that may be irreplaceable.
A weather pattern more conducive to bush fires could reemerge in coming weeks, considering Australia has seen some of its worst historical fires in January and February. However, some of the large-scale patterns that favored hot and dry conditions in Australia this spring and summer, such as an atmosphere-ocean cycle known as the Indian Ocean Dipole, have returned to a more neutral position.
However, other factors at work, including climate change, are still raising the odds of a hotter and drier rest of the Australian summer season.