Does sheet lightning pose the same threat as bolt lightning?
The term sheet lightning generally refers to long channels of lightning that appear horizontal. This is often seen at the base of clouds in the 10,000- to 15,000-foot range, and may be at the bottom of a thunderstorm’s anvil cloud. The horizontal–or sheet–portion of the flash may strike the ground some distance away. Think of the flash as having an upside down “L” shape, where there is a connection to ground and a long horizontal section along the base of a cloud. Flashes have been observed by special lightning detection systems that have one ground strike point that is connected to a horizontal segment up to 54 miles (90 kilometers) long!
