English: The skies over central Russia continued to be choked with heavy smoke from dozens of wildfires even as clouds moved over the region in late July 2016.

This true-color image was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Aqua satellite on July 25.

Numerous red hot spots speckle the green boreal taiga (forest) in the central section of the image. Each red hot spot is a thermal anomaly – a spot where the thermal sensors on the instrument detected abnormally high temperatures. When combined with typical smoke, as in this image, such hot spots are diagnostic for actively burning fire.

Heavy, light gray smoke rises from the fires and blows in various directions, suggesting winds that are both strong and variable. The smoke coalesces in a very thick gray blanket that appears to rise up close to the clouds, or may even mix with the cloud cover, especially in the west of the image. The cloud cover in the southeast section of the image suggests a storm system, with some possibility of rain.

The image is centered on the Sakha (Yakutia) Republic. Information from Russia regarding the wildfire situation in 2016 is sparse, but RIA Novosti reported that a wildfire had destroyed nearly 3,000 acres of woods the Lena Pillars Nature Park by July 7 and that a second fire had consumed over 1,900 hectares in the Mirny area. The Siberian Times reported the fire at the Lena Pillars Nature Park began on June 28 and were reported extinguished on July 21.

While the number of hotspots suggests dozens of fires burn across central Russia, the heavy smoke may suggest that at least some of the fires are burning in peat soil. Peat soils contain high levels of organic matter and are often damp, burning slowly with copious smoke. Peat fires can be hard to extinguish, as the fires in this media can smolder at a very low level underground, only to re-ignite when exposed to oxygen again – sometimes months after the fire was believed to be extinguished.