HOW A
HURRICANE FORMS
How does a
hurricane form? Do they just form when Mother Nature gets angry? No they don’t,
hurricanes form in tropical regions. They form there because they need warm water
of at least 80º Fahrenheit, high humidity with moist air, light winds, and very
warm surface temperatures. Summer and the early fall months are perfect for
hurricanes to brew up in the oceans around us. Most of the Atlantic hurricanes
brew up on the coast of Africa. For that the northern hemisphere hurricane
season is considered through the months of June and November.
The first sign of a
hurricane is a cluster of thunderstorms over tropical oceans. After the cluster
of thunderstorms arrives they will break away and become better organized. It
can take anywhere from hours to several days for a thunderstorm to actually
turn into a hurricane. Three things must happen for a hurricane to form though.
A continuous evaporation and condensation cycle must take place, patterns of
winds that are characterized by the converging winds, and a difference in air
pressure between the surface and high altitude.
Warm and moist air
from the ocean will begin to rise at rapid rates. As this warm air rises the
water vapor condenses to form dark storm clouds and droplets of rain. Surfaces
pressures begin to decrease as water vapor condenses and releases latent heat
into areas where the tropical disturbance is located. (Latent heat is heat
energy that is released during the phase change of water vapor.) This latent
heat causes the air to become less dense. The warm air then rises; as it rises
it becomes cooler and expands. That triggers more condensation and releases
more latent heat, which allows more air to rise. A chain reaction is now in
place. The exchange of the heat from the surface creates a pattern of wind that
moves around the center.
Then converging
winds—which are winds moving in different directions that run into each
other—converging winds at the surface collide and then push warm air downward
and the moist air upward. The rising air backs up the air that is already
rising from the surface. So then, wind speeds of the storm increase. In the
meantime, strong winds that are blowing at high speeds and at high altitudes
help to remove the hot rising air from the storms center. But if there are wind
shears (Wind shears are when directions of wind and speed differ.) the storm
will weaken.
If there are aren’t
any wind shears the storm’s air in the upper atmosphere will rise to higher and
higher pressures. Therefore the air cycle and hurricanes growth will get bigger
and bigger. There you have your hurricane.