Imagine seeing this outside your window!
On June 12, 2009 the International Space Station was flying over the Kuril Island chain in the northwestern Pacific when they witnessed the eruption of Sarychev peak, an active volcano on Russia's Matua Island.
Because the eruption had just begun, brown ash and steam was still rising in a mushroom cloud that had punched a hole in the cloud cover above it. Meanwhile, dark brown ash rolled low to the ground, probably a pyroclastic flow of hot gas and rock up to 1,850oF (1000oC) and traveling at 450 mph!
The ash had just begun to spread out in the sky (light brown at top left and right). Soon commercial air traffic was diverted to avoid engine failure from this abrasive particulate in the upper atmosphere.
The astronauts were lucky to see this eruption as it began.
Nature makes an impressive mushroom cloud.
(photo from the International Space Station, NASA)