VOLCAN CALBUCO, CHILE
This breathtaking combination of lightning and volcanic eruption took place in Chile in 2015, and is known as a dirty storm. In a dirty storm, the black plume billowing out of a volcano's crater carries red-hot ash and rock fragments that jostle and collide with each other as the smoke spews upwards. These collisions create static electric charges that build until they can longer be contained, at which point they're discharged as bolts of lightning that arc upwards through the plume. A 2016 study of dirty storms over Sakurajima volcano in Japan suggested that volcanic lightning could indicate the size of a volcano's ash cloud and could therefore be used as a basis for providing air quality warnings to the surrounding area.