Following a devastating early start to the summer fire season in Australia, wildfires fueled by wind and scorching heat have continued to burn across the southeast, where most of the country’s population lives.

Fire detections in southeast Australia Last 24 hours Last seven days Since October 2019 Brisbane Urban area AUSTRALIA Detail QUEENSLAND Tasman Sea NEW SOUTH WALES Newcastle NORTH 100 MILES Sydney Canberra Mallacoota VICTORIA Melbourne Fire detections in southeast Australia Last 24 hours Last seven days Since October 2019 Brisbane AUSTRALIA Urban area Detail QUEENSLAND NEW SOUTH WALES NORTH Newcastle 100 MILES Sydney Canberra Mallacoota Tasman Sea VICTORIA Melbourne Source: NASA Fire Information for Resource Management System. Data as of Jan. 13.

Fires have scorched millions of acres of land across Australia since October, destroying nearly 2,000 homes and killing at least 27 people, including three volunteer firefighters. The southeastern states of New South Wales and Victoria have been hit hardest.

Thousands of residents and tourists across the two states have been forced to evacuate. Hundreds of millions of animals are estimated to have been killed or displaced by the flames.

NEW SOUTH WALES Newcastle Sydney AUSTRALIA Sydney Canberra VICTORIA Smoke plumes from fires burning on Jan. 4 Mallacoota Melbourne 100 MILES NEW SOUTH WALES Newcastle AUSTRALIA Sydney Sydney Canberra VICTORIA Smoke plumes from fires burning on Jan. 4 Melbourne Mallacoota 100 MILES NEW SOUTH WALES AUSTRALIA Sydney Sydney Canberra VICTORIA Smoke plumes from fires burning on Jan. 4 Melbourne Mallacoota 100 MILES Source: NASA Suomi-NPP satellite.

Fires are common across northern Australia during the dry season, which runs between May and October, including planned burns. The southeast tends to burn between September and March, during the continent’s spring and summer.

Darwin A year of fire Active fires More intense Previous Northern Territory Queensland Western Australia Brisbane South Australia New South Wales Perth Canberra Sydney Victoria Melbourne Tasmania A year of fire Darwin Active fires Intensity Previous Northern Territory Queensland Western Australia Brisbane South Australia New South Wales Perth Canberra Sydney Victoria Melbourne Tasmania A year of fire Darwin Active fires Intensity Previous Northern Territory Queensland Western Australia Brisbane South Australia New South Wales Perth Canberra Sydney Victoria Melbourne Tasmania A year of fire Active fires Darwin Intensity Previous Northern Territory Queensland Western Australia Brisbane South Australia New South Wales Perth Canberra Sydney Melbourne Victoria Tasmania Source: Fire location analysis by Descartes Labs based on NASA MODIS data. Data reflects a one-week rolling average for Jan. 10, 2019, to Jan. 10, 2020.

The current fire season started early in the southeast and has been exceptionally brutal, experts said, even for a country used to regular burning.

Data from two NASA satellites that can detect the infrared radiation emitted by fires shows that 2019 was the region’s most active fire year in two decades, with the most populous state, New South Wales, worst affected. The state is home to Sydney, Australia’s largest city.

The fire crisis has continued into 2020, with some areas facing repeated threats.

Total fire detections in southeast Australia each year 60,000 fire detections (cumulative) 2019 50,000 40,000 30,000 20,000 2020 Other years, 2001 to 2018 10,000 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total fire detections in southeast Australia each year 80,000 fire detections (cumulative) 70,000 60,000 2019 50,000 40,000 30,000 20,000 2020 Other years, 2001 to 2018 10,000 Jan Dec Total fire detections in southeast Australia each year 80,000 fire detections (cumulative) 70,000 60,000 2019 50,000 40,000 30,000 Other years, 2001 to 2018 20,000 2020 10,000 Jan Dec Total fire detections in southeast Australia each year 60,000 fire detections (cumulative) 2019 50,000 40,000 30,000 20,000 2020 Other years, 2001 to 2018 10,000 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Source: Cumulative sum of fire detections in New South Wales, Victoria and Australia Capital Territory based on NASA Terra and Aqua satellite data. Data as of Jan. 10.

Rob Rogers, deputy commissioner of the New South Wales Rural Fire Service, called the fires “unprecedented.”

The last time New South Wales burned on a similar scale was in 1974, but those fires were in more remote areas of the state. This season, infernos have burned along the coast, often encroaching on popular tourist destinations and casting a thick haze over major cities.

Annual fire detections in southeast Australia 2001 2002 2003 2004 2005 NEW SOUTH WALES Sydney Canberra VICTORIA Melbourne 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 NEW SOUTH WALES Sydney Canberra VICTORIA Melbourne Annual fire detections in southeast Australia 2001 2002 2003 2004 NEW SOUTH WALES Sydney Canberra VICTORIA Melbourne 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 NEW SOUTH WALES Sydney Canberra VICTORIA Melbourne Annual fire detections in southeast Australia 2001 2002 2003 NEW SOUTH WALES Sydney Canberra VICTORIA Melbourne 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 NEW SOUTH WALES Sydney Canberra VICTORIA Melbourne Source: NASA Fire Information for Resource Management System

Why is this year’s fire season so brutal?

A combination of record-breaking heat, drought and high wind conditions have dramatically amplified the recent fire season in Australia.

Government records released shortly after the year ended confirmed that 2019 was the country’s hottest and driest year on record.

2019 was Australia’s hottest year. And its driest. 1974 2019 Annual rainfall difference from average +1.5° warmer than average +200 millimeters Annual temperature above or below the 1961–1990 average. 1980 +100 +0.5° –0.5° –100 1902 2019 1917 2019 was Australia’s hottest year. 2019 +1.5° warmer than average 1998 Annual temperature above or below the 1961–1990 average +0.5° –0.5° 1917 1974 And its driest. +200 millimeters Rainfall difference from average +100 –100 1902 2019 2019 was Australia’s hottest year. 2019 +1.5° warmer than average Annual temperature above or below the 1961–1990 average 1998 +0.5° –0.5° 1917 1974 And its driest. +200 millimeters +100 –100 Rainfall difference from average 1902 2019 Source: Australian Government Bureau of Meteorology

The last month of 2019 saw particularly low rainfall, and the country recorded its hottest day yet.

The combination of extremely dry and extremely hot conditions adds up to more powerful fires, said Crystal A. Kolden, a wildfire researcher at the University of Idaho.

“When the vegetation is just dry, it will burn,” she said. “But when you add this extreme heat, it magnifies the effect, allowing it to burn that much more intensely.”

Rainfall deficiencies from January 2017 through December 2019 Darwin Severe or serious deficiency Brisbane Lowest rainfall Perth Sydney Canberra Melbourne Darwin Severe or serious deficiency Lowest rainfall Sydney Melbourne Source: Australian Government Bureau of Meteorology

The Intergovernmental Panel on Climate Change, a group of scientists convened by the United Nations to assess major research on global warming and related climate impacts, found that the number of days with high-risk fire weather are expected to increase across southern Australia as the world warms.

This year’s early and intense fire season is “a harbinger of what is to come,” Dr. Kolden said, and a “strong indicator” that some of the effects of climate change are already here.

Here’s information on how to help the victims of Australia’s fires.