[4][5] Moist convection currents and ice formation also drive the eruption plume dynamics[6][7] and can trigger volcanic lightning.

[8][9] Unlike ordinary thunderstorms, volcanic lightning can also occur when there are no ice crystals in the ash cloud.

[20] Ice charging is thought to play an important role in certain types of eruption plumes—particularly those rising above the freezing level or involving magma-water interaction.

[32] Research continues, and the electrification via radioisotopes, such as radon, may in some instances be significant and at various magnitudes a somewhat common mechanism.

In taller ash plumes (7–12 km) large concentrations of water vapor may contribute to lightning activity, while smaller ash plumes (1–4 km) appear to gain more of their electric charge from fragmentation of rocks near the vent of the volcano (fractoemission).

Colder ambient temperatures promote freezing and ice charging inside the plume, thus leading to more electrical activity.

[36][37] These tiny glass spherules form during high-temperatures processes such as cloud-to-ground lightning strikes, analogous to fulgurites.