Ahead of a cold front moving from southwest to northeast, strong, dry winds out of the northwest helped instigate new blazes, vaulting embers from fire lines into areas not already ablaze. The fires knocked out power and water in some communities and forced the government to call up the military to assist in firefighting efforts.
As of Saturday evening, the Rural Fire Service of New South Wales still had emergency warnings, the most severe level, in effect. These warnings were communicated using dire language: “The fire is spreading quickly. If you are in Tallong, Werai, Exeter, Manchester Square, Avoca, Fitzroy Falls, Barrengary or surrounding areas it is too late to leave. Seek shelter as fire approaches,” read one such warning for the Morton Fire.
Particularly hard-hit on Saturday were the southern highlands, a wine-growing region about 70 miles southwest of Sydney, where high winds caused flames to surge northward into populated areas.
It’s unusual for bush fires to rage throughout the night, given that temperatures tend to drop overnight, but during Saturday night local time a sustained period of high winds caused flames to continue to spread rapidly.
Because the cold front is still making its way through the area of most intense fire activity, the hottest part of the day came and went with little to no relief. This allowed temperatures to soar to what appears to be a record-high temperature for Sydney, with Penrith, located in the far western reaches of the metropolitan area, hitting 120 degrees (48.9 Celsius). In addition, Canberra, the nation’s capital, hit a record high of 110 degrees (43.6 Celsius), breaking the previous record of 109 degrees set in 1939.
Many of the fires that intensified Saturday developed smoke plumes that were vaulted high into the atmosphere. Some turned into what are known as pyrocumulonimbus clouds, which are thunderstorms birthed by the combination of rising heat, smoke particles and water vapor from a major fire. At one point on Saturday, Australia’s Bureau of Meteorology issued a thunderstorm warning for storms generated by smoke plumes.
These pyroCb clouds, as they are known in the meteorology community, typically indicate that a fire is exhibiting extreme behavior, since they help a blaze draw in more surrounding air and can shift surface winds while also giving rise to fire tornadoes. A young firefighter in Australia died when a fire tornado overturned his vehicle.
On Friday into Saturday, fires also erupted in other parts of Australia, including a destructive blaze on Kangaroo Island in South Australia. That island is home to a nature preserve that contains numerous unique species. Fires have devastated habitat for iconic animals that are only found in Australia, including koalas and rare birds, though the toll on wildlife will not be fully known for some time.
Bush fires are expected to continue burning through the weekend and in the weeks and months to come as Australia enters its dry season in a precariously hot and desiccated position. However, the fire weather forecast for the next few days features cooler weather, which could help weary firefighters hold flames back behind containment lines.
Last year was the hottest and driest year on record in the country, and December turned out to be one of the top two hottest months ever recorded. December featured the country’s hottest day on record as well. No significant rain is expected in the hardest-hit areas of New South Wales and Victoria for months.
While bush fires are a regular occurrence during the Australian dry season, a combination of long-term climate change and natural variability is making the situation far worse.
The combustible climate mix
Human-caused global warming is raising the odds of and severity of extreme-heat events and also adding to the severity of wildfires by speeding the drying of the landscape, among other influences. One of the most robust conclusions of climate studies has been that human-caused warming would increase the frequency and severity of heat waves and also boost the occurrence of days with extreme fire danger.
Both trends are playing out in Australia, a country that has recently seen other severe climate impacts in the form of marine heat waves that devastated parts of the Great Barrier Reef.
The southern part of Australia has warmed by 2.7 degrees since 1950, according to climate researcher Zeke Hausfather, climate and energy director at the Breakthrough Institute. This is consistent with the period of faster human-caused warming worldwide.
The unusually warm and dry year in Australia is also due, in part, to a weather pattern that has set up across the Indian Ocean. It’s known as the Indian Ocean Dipole, or IOD, which is an air circulation pattern in the Indian Ocean. When the IOD is in its positive phase, the water is cooler than average off the coast of Sumatra, leading to reduced atmospheric lift there and reduced rainfall over Australia, and there are warmer-than-average waters off the coast of Africa.
A positive IOD the past two years has meant drier-than-average conditions in much of Australia. The Bureau of Meteorology found that it is unusual to have back-to-back years with a positive dipole, which helps influence precipitation patterns across South Asia and Oceania.
This natural climate cycle is changing over time as ocean and air temperatures rise in response to increased amounts of greenhouse gases from human activities, namely the burning of fossil fuels for energy. This is expected to make back-to-back positive IOD events more common and make Australia even more prone to drought conditions accompanied by extreme heat.
“While the IOD is a natural mode of variability, its behavior is changing in response to climate change. Research suggests that the frequency of positive IOD events, and particularly the occurrence of consecutive events will increase as global temperatures rise,” the bureau stated.
The scale of the ongoing disaster in Australia is difficult to fathom even for those on the ground. At least 12 million acres have gone up in smoke so far in Victoria and New South Wales alone, which dwarfs the amount of land that burned in California’s worst fire season in 2018. It is equivalent to the burning of the entire state of West Virginia.
Smoke from the blazes has made it to South America, a journey of 9,000 miles, and some may stay aloft for months, having a small effect on the planet’s climate.
On the ground, though, residents in affected areas feel helpless and scared, and increasingly weary.
Rebecca Butterworth, a house painter and journalist in Albury, a city in southern New South Wales, says it has been surreal to hear the small towns in the picturesque Murray-Darling Basin, some of which have populations under 100, mentioned on national newscasts.
“The signal for ‘leave’ is a red rimmed triangle with a black interior, and a little traffic light guy at full hock within it. It’s just hanging everywhere,” she said in an email.