Thick, black, billowing smoke rises over North Cascade, Western Australia in this image taken by NOAA/NASA’s Suomi NPP satellite on February 21, 2019. These bushfires were first reported on or about Feb. 20, 2019. This is a remote area of Australia and as such the warnings issued by the Government of Western Australia’s Emergency WA site (Department of Fire and Emergency Services) are categorized as “Bushfire Advice.” This means the following:
- There is no threat to lives or homes.
- There is a lot of smoke in the area.
- Although there is no immediate danger you need to be aware and keep up to date in case the situation changes.
What is striking in this photo, however, is the color of the smoke rising from these fires. Ordinarily smoke from a wildfire or bushfire is white or grayish in color. This smoke is darker, almost black. The reason is that a hotter fire tends to convert more fuel to carbon, which breaks down into small particles that absorb the light, thus appearing in the sky as black smoke. A cooler fire yields less elemental carbon as it uses the moisture in the fuel. This type of emission tends to reflect the light which makes the smoke take on a gray or white hue. Wildfires can produce both smoke colors. The driest fuel will combust and release black smoke whereas large branches and tree trunks which still have moisture within will release a whiter smoke upon burning.
NASA’s Suomi NPP satellite collected this natural-color image using the VIIRS (Visible Infrared Imaging Radiometer Suite) instrument on February 21, 2019. Actively burning areas, detected by MODIS’s thermal bands, are outlined in red. NASA’s Earth Observing System Data and Information System (EOSDIS) Worldview application provides the capability to interactively browse over 700 global, full-resolution satellite imagery layers and then download the underlying data. Many of the available imagery layers are updated within three hours of observation, essentially showing the entire Earth as it looks “right now. Caption by Lynn Jenner with information from Emergency WA.