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| Cloud-to-ground lightning bolts are the most
familiar and the most dangerous. Most cloud-to-ground
lightning strikes come from the negatively charged bottom of
the cloud to the positively charged ground below. Often,
cloud-to-ground lightning bolts strike the highest object,
like the top of a building or the highest limb on a tree.
The lightning strikes can cause fire and property damage. If
a human being is the highest object in the lightning bolt's
path, the strike can cause severe injury or death. Although
cloud-to-ground lightning is the most dangerous, it is also
the most understood because it leaves so much evidence
behind. |
| Most cloud-to-ground lightning strikes bring
negative energy down to the ground, but some strikes deliver
positive charge to the ground. Positive strikes are less
common and emerge from the higher regions of the
thundercloud. Some meteorologists believe that positive lightning
strikes indicate storms that are more likely to spin out
tornadoes. |
| Not all lightning bolts strike the ground.
Many lightning discharges occur within and between
thunderclouds. The most common type of lightning, called
intracloud lightning, strikes between positive and negative
areas in the same cloud. The bolt is not usually visible,
but rather appears like a broad flash in the sky. A less
common lightning strike occurs between oppositely charged
areas of separate clouds. Known as intercloud lightning, the
strike passes through clear air and provides a stunning bolt
of light. Intercloud lightning poses a particular hazard to
airplanes in flight because it passes through the clear air
between clouds. |
