image: In 2016, NASA predicted a very active fire season for Brazil's Amazon in this article published in June 2016. The cause of the severe season was the El Niño that was in effect at the time. In 2016 this area (Mato Grosso) during the week of Sept 7 - Sept. 14 saw 48,618 fires. This year the total of fire alerts was 39,967 for the same area and the same time frame. So there are less fires than were seen in 2016 when the area was seen as having a significant and severe. However, this year hasn't seen a huge downtick in the number of fires meaning some of the same issues are creating fire hazards in the Amazon. These include hot, dry conditions as well as "slash and burn" agriculture which is practiced in this part of the world.
The generally infertile soils of the Amazon rainforest--the largest such forest on Earth--make sustainable farming difficult. Because of this farmers have to continually create new farm land from forest land. The area of clearing can be considerable and the easiest method to accomplish this is to burn out the land needed for the next crop.
NOAA-NASA's Suomi NPP satellite collected this natural-color image with the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument on September 12, 2017. Actively burning areas, detected by MODIS's thermal bands, are outlined in red.
Credit: NASA image courtesy Jeff Schmaltz LANCE/EOSDIS MODIS Rapid Response Team, GSFC. Caption by Lynn Jenner with information from Global Fire Watch as well as a NASA story on Amazon fire published in 2016.