Stock Photo: Arc of cloud-to-cloud lightning below the cloud base at sunset. This is a rare shot of scientific interest, as it appears to represent a single discharge channel. Avra Valley, Arizona, USA.

Stock Photo: 1899-49889 Arc of cloud-to-cloud lightning below the cloud base at sunset. This is a rare shot of scientific interest, as it appears to represent a single discharge channel.    Avra Valley, Arizona, USA.