Structurally, Hurricane ( a tropical cyclone ) is a large, rotating system
of clouds, wind and thunderstorm activity. The primary energy source of a
tropical cyclone is the release of the heat of
condensation from water vapor condensing at high altitudes.
Because of this, a tropical cyclone can be thought of as a giant vertical
The ingredients for a tropical cyclone include a pre-existing
weather disturbance, warm tropical oceans, moisture, and relatively light
winds aloft. If the right conditions persist long enough, they can combine
to produce the violent winds, incredible waves,
torrential rains, and floods associated with this phenomenon.
Condensation as a driving force is the primary difference which
distinguishes tropical cyclones from other meteorological phenomena.
Mid-latitude cyclones, for example, draw their energy mostly from
pre-existing temperature gradients in the atmosphere. In order to continue
to drive its heat engine, a tropical cyclone must remain over warm water,
which provides the atmospheric moisture needed. The
evaporation of this moisture is driven by the high winds and
reduced atmospheric pressure present in the storm, resulting in a sustaining
cycle. As a result, when a tropical cyclone passes over land, its strength
will diminish rapidly.