the april 2010 volcanic eruptions in eyjafjallajokull, iceland (previously featured). known as a dirty thunderstorm, this phenomenon is yet to be explained by science, as the source of the lightning (or the specific mechanism by which particles of differing charges are separated in the ash cloud) continues to be debated.

see also the sakurajima eruptions. photos by skarphedinn thrainsson, gunnar gestur geirmundssonsigurdur hrafn stefnisson, lukas jackson and ragnar th sigurdsson.