An early summer heatwave swept over large parts of Australia on December 16-17, 2023, helping to fuel dozens of bushfires in New South Wales.
The map above shows modeled air temperatures across Australia on December 16. It was produced by combining satellite observations with temperatures predicted by a version of the GEOS (Goddard Earth Observing System) model, which uses mathematical equations to represent physical processes in the atmosphere. The map represents temperatures at about 2 p.m. Australian Eastern Daylight Time, and the darkest reds indicate areas at or above 45 degrees Celsius (113 degrees Fahrenheit).
The heatwave was especially intense in Western Australia, where temperatures reached above 40°C (104°F), which is up to 10°C (18°F) above normal for the time of year, according to the country’s Bureau of Meteorology. On December 16, the remote mining town of Telfer recorded 45°C (113°F), the highest temperature recorded anywhere in the country on that day. The heatwave also extended to the eastern parts of Australia. Temperatures in Brisbane reached 33°C (91°F) that day, and Sydney airport reached 34°C (93°F).
The hot, dry conditions heightened the risk of bushfires in Western Australia, Northern Territory, and New South Wales. Near Narrabri, New South Wales (360 kilometers northwest of Sydney), a fire broke out in Pilliga Forest and quickly spread to cover 121,000 hectares (300,000 acres) by December 18. Smoke can be seen billowing from the fire in the image above, acquired by the OLI (Operational Land Imager) on Landsat 8 on December 17. Smoke drifted east from the fires and filled the skies in Sydney, causing poor air quality, according to news reports.
Though Australia’s fire season does not peak until January or February, the season has already been unusually active. According to Global Forest Watch, which uses data from NASA’s FIRMS (Fire Information for Resource Management System), fire detections this year have already been twice as high as the 2019-20 “black summer,” when catastrophic wildfires—unprecedented in their scale and intensity—scorched eucalyptus forests in southern and eastern Australia. The European Union’s Copernicus Atmosphere Monitoring Service recently calculated that carbon emissions from fires in Australia for September-November 2023 were just over 150 million tons, the highest since 2012.
Meteorological summer in Australia begins in December, but the country has already been hit by other instances of extreme heat. High temperatures also swept New South Wales in September and again in early December, when the airport in Sydney recorded 45.7°C (114.3°F), the highest temperature recorded at the station since it began making observations in 1929.
NASA Earth Observatory images by Wanmei Liang, using GEOS data from the Global Modeling and Assimilation Office at NASA GSFC and Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.