File:Fires in southwestern Australia (MODIS 2017-04-08).jpg

English: While northeastern Australia struggles with flooding brought by Tropical Cyclone Debbie, drier weather in southwestern Australia has set the stage for a different natural hazard: fire.

On April 4, 2017, the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Aqua satellite captured this true-color image of southwestern Australia. Dozens of red hot spots speckle the landscape, especially in the grassland regions. Each red hot spot marks an area where the thermal bands on the MODIS instrument detected an area hotter than background. When combined with typical smoke, as in this image, such hot spots mark actively burning fire.

Typically the month of April is a dry one in this region and, as such, is considered part of “bush fire season”. More than 80% of the rainfall in southwestern Australia falls between May and October, with mean monthly averages of less than 25 mm (1 inch) during February, March, and April. In addition, the climate of the region has been trending drier since the mid-1970s, with an annual rainfall reduction by as much as 20%. This trend towards a drier climate increases fire risk, and that, in turn, has encouraged increased fire management – including prescribed burns. Prescribed burns are deliberately set fires which are carefully controlled and are used to manage land, particularly reducing fuels which may feed devastating wildfires.

Rains began to fall earlier than typical in 2017, with a dampening of the grasslands occurring in late March. Since prescribed burning is best used when fuel loads are high, but fire risk is low (yet not during heavy rains), they are often utilized as the autumn rains begin to fall. The early onset of rains have made conditions in southwestern Australia right for managed burns even before the typical onset of the “rainy” season in May. The fires in the region are a mixture of bush fire (wildfire) and prescribed burns.