Volcanoes trigger lightnings
Volcanic activity produces lightning-friendly conditions in multiple ways. The enormous quantity of pulverized material and gases ejected into the atmosphere with explosive power, creates a dense plume of highly charged particles, which establishes the perfect conditions for lightning. The ash density and constant motion within the volcanic plume continually produces electrostatic ionization, resulting in very powerful and very frequent flashes attempting to neutralize itself. Due to the extensive solid material (ash) content, unlike the water rich charge generating zones of a normal thundercloud, it is often called a dirty thunderstorm.