English: Multiple wildfires were burning in northern Saskatchewan, Canada in early July 2021. The Moderate Resolution Imaging Spectroradiometer (MODIS) on board NASA’s Aqua satellite acquired a true-color image of at least eight fires burning on July 1. Strong winds blow long plumes of smoke eastward in the northernmost fires. The smoke is so thick in many areas that it is not possible to see the ground through the smoke.

Each red “hot spot” marks an area where the thermal bands on the instrument detected high temperatures. When combined with typical smoke, as in this image, such hot spots are diagnostic for actively burning fire. In general, the size of the hot spot corresponds to the size of a fire, with a small fire showing a small hot spot. Large fires, however, may have multiple hot spots as the fresh fuel on the edge of the fire burns while the areas where all fuel has been consumed has cooled.

According to the Saskatchewan government, as of July 2 there were 18 active wildfires in the province, with seven listed as “uncontained”. There have been 206 wildfires in Saskatchewan this year, which is higher than the 5-year average of 195. As of the morning of July 3, the Natural Resources Canada interactive map shows at least 5 of the “out of control” fires are larger than 1,000 hectares in size. This map estimates the size of the five fires shown in the northeast section of the image and sitting in a line from north to south as: 3,000 hectares, 10,000 hectares, 1,600 hectares, 273 hectares and 1.5 hectares.