Lightning that's hidden
| Lightning doesn't always strike the ground. A stroke of lightning can travel from one part of the cloud to another part of the same cloud ("intra-cloud lightning"), from one cloud to another cloud ("inter-cloud lightning"), or from a cloud to the ground ("cloud-to-ground lightning"). There have even been reports of lightning travelling up from the top of a cloud and disappearing into thin air. |
Credit: NOAA Photo Library
For more info: http://www.nssl.noaa.gov/researchitems/lightning.shtml