This week’s Plane & Pilot Photo Of The Week is of a pyrocumulus cloud, otherwise known as a cumulonimbus flammagenitus. This cloud type is formed by fires burning on the surface. Heat rises, causing instability, which in turn causes the cloud to form. This photo, from a source who chose not to be credited (but thank you anyway), was taken between Fort Collins and Denver, Colorado, at 21,000 feet.
In rare instances, pyrocumulus clouds have been known to rain so hard that they put out the fire that created them. Unfortunately, this did not happen in this instance.
Note: The photo was retouched, but only in order to remove numerous bug spots on the windscreen.