During the end of the 2022-2023 bushfire season in southern Australia, intentional fires caused smoke to fill the skies south of Perth. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite captured the smoke in an image taken on April 23, 2023. Most of the sources of smoke in the image matched the locations of prescribed burns listed on a map by Emergency WA.
The Department of Biodiversity, Conservation, and Attractions (DBCA) in Western Australia reported that the summer and early autumn of 2022-2023 were drier than usual. However, mid-autumn saw plentiful rainfall, setting the stage for prescribed burning to begin. By the end of April, dozens of blazes were burning across the state's southwest.
Prescribed burns are conducted to reduce the build-up of flammable fuels and minimize the severity of bushfires. They can also be used to maintain biodiversity or to rehabilitate vegetation after land disturbance. Despite being planned with meteorological conditions in mind, winds can still carry the smoke far from the source. In this case, winds moved the smoke plumes towards the southeast and, in some instances, over the Indian Ocean.
While most of the fires in the image were intentionally set, some were not. Smoke from a fire near the Lake Muir Nature Reserve was likely a bushfire, located just south of a prescribed burn. The Parks and Wildlife Service issued a smoke alert for the area, warning of reduced visibility and potential health effects for people with respiratory or cardiovascular illnesses.
Stefan de Haan of DBCA thanked the community for their understanding and urged people to drive carefully if smoke was affecting visibility on the roads. The image was captured by Lauren Dauphin of NASA Earth Observatory using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview. The story was reported by Kathryn Hansen.