SYDNEY — Raging fires stretching across a distance half the length of the California coastline killed at least three people and destroyed more than 150 homes in Australia over the weekend. Senior firefighters warned Sunday the blaze could become so dangerous in coming days that they might not be able to protect lives and property.
From Crowdy Bay National Park on the coast of New South Wales state to just north of the affluent beach town of Noosa in adjacent Queensland state — a distance of 460 miles — emergency agencies were struggling to bring some 70 bush fires under control.
Eastern Australia’s major north-south road, the Pacific Highway, was cut off by fire and smoke about five hours north of Sydney near the township of Johns River, where the body of a 63-year-old woman, Julie Fletcher, was found in her burned home.
Fletcher had messaged a neighbor that she had decided to abandon her house to the flames, which witnesses in the area said had became a wall 20 feet high that emitted smoke so thick it blotted out the sun.
‘‘I got a message from her at 9:30 p.m. on Friday night saying she was putting her things in the car and getting ready to go,’’ Diny Khan told Sydney newspaper the Daily Telegraph. ‘‘She obviously never made it out. What a horrible way to go.’’
Two other people died in the small town of Wytaliba near the Guy Fawkes River National Park, a reserve popular with bushwalkers and birdwatchers. A 69-year-old woman, Vivian Chaplain, died in a hospital of severe burns after trying to protect her home, and a man, George Nole, was found inside a burned car, authorities said.
Satellite photographs showed smoke from the fires billowing hundreds of miles across the Pacific Ocean toward New Caledonia.
An estimated 350 koalas died when fire swept through their breeding ground near the coastal city of Port Macquarie. Koalas typically breed once a year, and it will be difficult for the population to recover, according to Sue Ashton, president of the local koala hospital. ‘‘I don’t know how we are going to come back from this,’’ she told the television show ‘‘Today.’’
Temperatures are forecast to top 100 degrees on Tuesday and winds of up to 22 miles an hour will probably push the fires closer to the more-populated coast.
Emergency services are so concerned that conditions are going to deteriorate over the next two days that they have warned people that they cannot rely on help and should consider evacuating in advance.
‘‘Don’t wait for the last minute and ring for a firetruck, because it may not get there,’’ said Jeremy Fewtrell, deputy commissioner of New South Wales Fire and Rescue. ‘‘We just don’t want to lose more people.’’
Firefighters are trying to predict where the fires will shift so they can deploy equipment and move people out before their lives are threatened.
‘‘We’re not out of this yet,’’ Prime Minister Scott Morrison told reporters at a rural evacuation center for fire victims on Sunday. ‘‘There is a long way to go and Tuesday is looking more difficult.’’
External fires, including wood barbecues, have been banned in New South Wales on Monday and Tuesday, and for the first time, bush fire conditions have officially been classified as ‘‘catastrophic’’ — the highest threat level — in the greater Sydney region.
Bush fires are responsible for more mass casualties in modern Australian history than any other natural disaster, and the penalty for breaching the fire ban is a year in jail.
Many Australian environmentalists fear that bush fires are becoming more common as the planet warms. They accuse Morrison’s center-right government of not doing enough to combat climate change.
As Australia’s summers become longer and hotter, the dry countryside has become more susceptible to lightning strikes, lit cigarettes, and other bush fire triggers.
During a briefing from firefighters on Sunday, a protester yelled at the prime minister, ‘‘Climate change is real, can’t you see?’’
Asked if there is a link between bush fires and climate change, Morrison declined to answer directly. ‘‘I’m focused on the needs of the people in this room today,’’ he said.
Although the ongoing blazes have specific short-term causes, the long-term trends are clear, based on climate science reports. According to a 2015 climate assessment from the Australian government’s main science agency, the fires are burning in areas that are expected to see increases in fire risk due to the effects of human-caused global warming.
Studies published since then have also highlighted the lengthening of the fire season, and shown that conditions will become more conducive to severe fires as the climate warms and vegetation dries out faster and more extensively.
Australia is mired in a multiyear drought, and hotter-than-average conditions are exacerbating its impacts, according to the Bureau of Meteorology.
A local mayor, whose house was badly damaged in the fires, was more direct.
‘‘It’s climate change; there’s no doubt about it,’’ Carol Sparks, mayor of Glen Innes, told the Australian Associated Press.