Hurricanes

    In the western Pacific Ocean hurricanes are called typhoons.  To people living near the Indian Ocean they are called cyclones.  Near the Atlantic Ocean, the Caribbean, the Gulf of Mexico and Central America they are called hurricanes.  The neat thing about tropical cyclones is that in the Northern Hemisphere hurricanes turn counter clockwise, where in the Southern Hemisphere these storms turn clockwise.  Hurricanes occur most frequently in the late summer and early fall.  The map below shows the areas where these great storms occur most often.  

Movement of Hurricanes

    Hurricanes move according to wind currents that steer them.  Hurricanes in the Atlantic Ocean tend to move westward and turn north towards the north pole.  Cyclones and Typhoons move in a westward direction as well, but eventually move toward the south pole.  Open and print out the Hurricane Tracking map that is attached to the next web page.  You may use this map to track a hurricane for the 2001 hurricane season, or for upcoming seasons. Be sure to keep it somewhere so that all members of your family can locate it.

Stages of Hurricanes

    At this point in the lesson I am going to focus on the development of hurricanes in the Atlantic Ocean.  Hurricanes usually start out as a storm that comes off the west coast of Africa.  These storms begin to develop and are called tropical waves.  When this disturbance starts a small rotation and the winds begin to pick up and remain steady, the storm is now called a tropical depression.  When the wind speed in the storm is sustained between 35 and 73 mph the storm is now called a tropical storm and is given a name.  These names are from a list that the National Hurricane Center releases each year, once a name is given it will never be used again.  If pressure inside the storm continues to fall and the winds continue to pick up and become sustained at 74 mph or greater the storm is called a hurricane.

Characteristics of a Hurricane

    Once a storm reaches hurricane status the most famous  characteristic starts to form, the eye.  The eye is the calm center of the storm, it is a phenomenon that occurs because of the Coriolis effect.  The strongest winds in a hurricane usually concentrated in a band immediately surrounding the eye called the eye wall.

Classifying Hurricanes

    Hurricanes are classified by the Saffir-Simpson hurricane scale.  This scale classifies hurricanes according to wind speed, air pressure, and potential for property damage.  The Saffir-Simpson scale is located below.

Hurricane Hazards