Lightning

Lighting during the Eyjafjallajökull eruption 2010. Photo taken 17 April 2010 by Thordur Arason.

Lightning is an electric current through air that occurrs when charge difference between two points in the air is quite high. The electric current causes a powerful electromagnetic wave in all directions. Thunderstorms are not common in Iceland comparted to more southerly countries. Information on measured lightning in Iceland for the past days can be found on IMO's webpage. 

Lightning can cause accidents on people, in which case you should always contact the emergency number 112 and start first aid if needed until help arrives. Lightning often cause damages to electrical equipment. The web of the Department of Civil Protection and Emergency Management provides someinformation on lightning hazards/protection in Icelandic.

Lightning during volcanic eruptions

Lightning are common during explosive volcanic eruptions. Processes in the ash plume can lead to electric charge separation similar to thunderstorms. Most volcanic lightning strike close to the eruption vent, but can also strike down tens of km from the eruption site. In the 1755 Katla eruption, two people were killed when hit by a volcanic lightning in Svínadalur in Skaftártunga, about 30-35 km from Katla.