House fire caused by a lighting strike. Lightning occurs when a large electical charge builds up in a cloud. The charge induces an opposite charge on the ground and a few 'leader electrons' travel to the ground. When one electron contacts the ground, there is huge back flow of energy up the path of the electron, producing a bright flash of light and causing temperatures of over 3000 degrees Celsius. It is this extreme temperature that often starts house, bush or forest fires. Photographed in Kansas, USA.