File:Fires in Northern Territory, Australia (MODIS 2021-06-23).jpg

English: Many dozens of fires were burning across Australia’s Top End on the first day of winter, 2021.

On June 21, the Moderate Resolution Imaging Spectroradiometer (MODIS) on board NASA’s Aqua satellite acquired a true-color image of fire and smoke across the northern portion of Northern Territory that captured multiple red “hot spots” and copious smoke rising from the region. Each of these hot spots mark an area where the thermal bands detected high temperatures. When combined with typical smoke, as in this image, such hot spots are diagnostic for actively burning fire.

Winter coincides with the dry season in the Northern Territory, and the start of winter marks the onset of the bushfire season. The Northern Territory received above average rainfall during the wet season, which ends in late April. By June the lush growth spurred by the generous rains begins to dry, resulting in above-average fire potential. This risk increases through the dry season.

While it’s not possible to determine the origin of a fire based on satellite imagery, given the time and distribution of these fires, most are likely to be bushfires. However, prescribed burns occur year-round in parts of Australia and agricultural fires may also occur at times. Agricultural fires are those fires deliberately set and managed to open fields, clear old crops, prepare soil for planting, freshen pasture or other agricultural use. Prescribed burns are generally set and managed on wildlands or other managed lands to reduce fuel loads and reduce risk of large and severely damaging wildfires.