With more than 100 bush fires raging in New South Wales alone, Australia is bracing for a new round of extreme fire weather this weekend, prompting the unprecedented evacuation of tens of thousands of people in coastal Victoria and New South Wales.

Weather during the next few days will be similar to what led to the bush fire crisis in the first place: building heat in the southwestern reaches of the country leading to “catastrophic” fire danger in some regions Thursday and at least “extreme” fire weather danger in South Australia on Friday. Even the city of Adelaide is expected to top 104 degrees (40 Celsius), with temperatures inland climbing even higher, with high winds.

The combination of the heat and strong winds associated with a frontal system will create explosive conditions for supporting extreme fire behavior, including their rapid and unpredictable spread. Similar conditions have already proved fatal to residents and firefighters, with the death toll as of Thursday standing at 17 for the season.

Capital Weather Gang's Andrew Freedman discusses what caused the fires taking over Australia — and what's to come. (The Washington Post)

While the country has experienced deadlier fire seasons, this one is noteworthy for the massive reach of the blazes — 10.1 million acres have burned in Victoria and New South Wales alone, an area larger than the state of Maryland. In addition, it’s only the start of summer in Australia, meaning that the fire season still has at least a few months to go.

Meteorologists and public officials have been issuing forecasts for unusually severe fire weather Saturday, which may be worse than the weather on New Year’s Eve, when blazes advanced on coastal communities, forcing residents to take shelter at sea.

“Conditions will be the same or worse than those experienced on New Year’s Eve,” said Jonathan How of the Bureau of Meteorology, in an online briefing. He cited “More hot temperatures, gusty winds and with a background of more fires burning through the landscape” as particular risks. As was the case during previous spikes in fire danger that affected areas near Melbourne, Sydney and smaller coastal towns in Victoria and New South Wales, Saturday is likely to feature a cold front moving northeastward with time.

However, this front may arrive later in the day than did past wind shifts, which means daily high temperatures could climb further than they did on New Year’s Eve and similar severe fire days during November and December. The southerly wind shift is perilous because it can cause any fires already burning to surge in a new direction, while bringing a period of higher wind gusts when compared with the rest of the day.

“It’s going to be a blast furnace” during the days ahead, Andrew Constance, the New South Wales transport minister, told the Sydney Morning Herald. He said the evacuations are the largest in the region’s history.

The ongoing blazes are the result of a combination of factors that have primed the region to burn. Australia just ended its hottest and driest year on record. In addition, December was one of the top two warmest months on record for the country and featured the hottest day recorded there, as well.

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.

The southern part of Australia has warmed by 2.7 degrees since 1950, according to climate researcher Zeke Hausfather of Berkeley Earth. This is consistent with the period of faster human-caused warming worldwide.