On May 18, 2014 the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Terra satellite flew over the Irkutsk region of Russia and captured this true-color image of dozens of fires filling the skies with thick gray plumes of smoke. By that date the early fire-season had progressed so rapidly that authorities had declared a state of emergency.
Each red hotspot marks a location with the thermal bands on the MODIS instrument detected temperatures higher than background. When combined with typical smoke plumes, such hotspots indicate actively burning smalls. MODIS has been detecting small fires in Irkutsk since May 14, mostly along rivers and near farmland. The fires increased in size and intensity on May 18, according to satellite imagery.
The St. Petersburg Times reported that 77 fires had burned more than 39,000 hectares (150 square miles) in Irkutsk by May 19. Fire destroyed 22 homes in the village of Dalny and forced the evacuation of hundreds of people, according to the Russian Emergencies Ministry (EMERCON).
The fires were so intense that they spawned several pyrocumulus clouds. One can be seen just above the center of the image, where the red hotspots coalesce to for an upside-down L shape. A broad band of gray smoke rises from the top of the hotspots. Right at the northern border of the hotspot there is a puffy, bright-white cauliflower-shaped cloud hovering over the darker smoke. This is a pyrocumulus, and is created by a column of air heated by fire rising, which then leads to cooling as it lifts, and condensation of water vapor in the column.