Weather Lightning Photography of Cloud to Cloud horizontal lightning striking over the foothills of the Rocky Mountains and water of a lake with reflections of lights. Fact: Cloud-to-cloud lightning- Multiple paths of cloud-to-cloud lightning, Swifts Creek, Australia Lightning discharges may occur between areas of cloud without contacting the ground. When it occurs between two separate clouds it is known as inter-cloud lightning and when it occurs between areas of differing electric potential within a single cloud, it is known as intra-cloud lightning. Intra-cloud lightning is the most frequently occurring type.
These are most common between the upper anvil portion and lower reaches of a given thunderstorm. This lightning can sometimes be observed at great distances at night as so-called “heat lightning”. In such instances, the observer may see only a flash of light without hearing any thunder. The “heat” portion of the term is a folk association between locally experienced warmth and the distant lightning flashes.
Another terminology used for cloud-cloud or cloud-cloud-ground lightning is “Anvil Crawler”, due to the habit of the charge typically originating from beneath or within the anvil and scrambling through the upper cloud layers of a thunderstorm, normally generating multiple branch strokes which are dramatic to witness. These are usually seen as a thunderstorm passes over the observer or begins to decay. The most vivid crawler behavior occurs in well developed thunderstorms that feature extensive rear anvil shearing. Source: Wikipedia