The Workings of a Hurricane

With winds of 155 miles per hour and higher, hurricane’s are one of the most destructive forces of nature.  Hurricanes are scientifically called a “tropical cyclone,” warm air at the center of a spinning cyclone, rotating around a low pressure point.

Hurricanes are formed over warm tropical waters with a sea surface temperature of 80 degrees Fahrenheit or warmer.  Light winds and a high humidity level are also needed conditions for hurricane development.

Hurricane development begins when thunderstorms appear in clusters over the oceans.  This is called a tropical disturbance.  The disturbance forms in an area of low air pressure.  Winds from nearby areas of higher air pressure move towards the center of the storm.

The oceans waters supply moisture and warmth to the disturbance, which is now developing into a tropical depression.  The oceans waters also provide energy to the storm, making the warm air in the storm center to rise fast.  When the warm air meets the higher cooler air it condenses, forming thunderstorms.

The surface wind for a tropical depression varies between 20 and 34 knots.  If these winds increase in speeds of at least 35 knots, a tropical depression is upgraded to a tropical storm.  Once winds reach a speed of 64 knots, it is then considered a hurricane.

As the air in the storm center continue to rise and condense it begins to produce heat, making the air to rise even faster.  As the air is pushed out of the top by the raising air, more air must come in through the bottom to take its place.  This is how hurricanes are able to feed itself and build more strength and energy.

The center of the hurricane is called the eye and often range 20 to 50km in diameter.  The eye of a hurricane is often clear skies, light winds and low air pressure.  The eye wall is made up of a ring of cumulonimbus clouds that twist around the eye.  Here, the strongest winds and heaviest precipitation is found.

Hurricanes are a spiraling shape due to the Coriolis Effect, which is caused by Earth’s rotation.  In the Northern Hemisphere the earth’s rotation causes the wind to go to the right, always rotating counterclockwise.  Storms in the Southern hemisphere rotate the opposite, in a clockwise manner.

Hurricane’s loose energy and strength when they move over cooler waters as their fuel supply begins to cool.  When over land, hurricanes loose their moisture source as well as heat.  Thunderstorms are no longer able to form near the center and the storm weakens and dies out.